Contact Details:
Professor Andrew J. Fleming
Director, Precision Mechatronics Lab
Director, Priority Research Center for Complex Dynamics systems and Control
Deputy Head of School (Research), School of Electrical Engineering and Computer Science
The University of Newcastle
Callaghan, NSW 2308, Australia
+61 2 4921 6493
Andrew(dot)Fleming(at)newcastle.edu.au
Biography
Andrew J. Fleming graduated from The University of Newcastle, Australia with a Bachelor of Electrical Engineering in 2000 and Ph.D in 2004. Professor Fleming is now the Director of the Precision Mechatronics Lab and the Priority Research Center for Complex Dynamic Systems and Control at The University of Newcastle, Australia. His research includes nanofabrication, micro-robotics, metrological sensing, nano-positioning, and high-speed scanning probe microscopy. Professor Fleming’s research awards include the ATSE Batterham Medal, the IEEE Transactions on Control Systems Technology Outstanding Paper Award, the University of Newcastle Researcher of the Year Award, and the Faculty of Engineering and Built Environment Award for Research Excellence. He is the co-author of three books and more than 190 Journal and Conference papers. Prof Fleming is the inventor of several patent applications and in 2012 he received the Newcastle Innovation Rising Star Award for Excellence in Industrial Engagement.
Awards/Fellowships
- Best Paper Award (co-author), IEEE Manipulation, Automation and Robotics at Small Scales, 2019, Helsinki, Finland.
- Research Supervision Excellence Award, University of Newcastle, 2017
- Batterham Medal, Australian Academy of Technology and Engineering, 2016
- Finalist, the Chancellor’s Award for Innovation, 2016
- Best Paper Award Finalist, IEEE Advanced Intelligent Mechatronics 2016
- ARC Future Fellowship 2014‐2017
- Newcastle Innovation Rising Star Award, 2012
- ARC Australian Research Fellowship 2009‐2013
- The University of Newcastle Vice Chancellors Award for Researcher of the Year, 2007
- Best Paper Award ‐ IEEE Transactions on Control Systems Technology, 2007
- Faculty of Engineering and Built Environment Award for Research Excellence, 2007
- ARC Australian Post‐Doctoral Fellowship 2006‐2008
Funding
- Total $10.7M
- 30 Grants, 12 ARC Grants
- 3 Fellowships (12 Years)
- Detailed Funding List
Supervised Student Awards
- Matheus Xavier – Second Place Award for Best Presentation at IEEE ICCMA 2019
- Meysam Omidbeike – Best Student Paper Finalist, IEEE MARSS 2019
- Meysam Omidbeike – Best Student Paper Finalist, IEEE AIM 2018
- Yik Ren Teo – Best Student Paper Finalist, IEEE MSC 2015
- Shannon Rios – Best Student Paper Finalist, IEEE AIM, 2015
- Mathew Fairbain – Best Student Paper Award, Australian Control Conference
Professional Activities
- Associate Editor for IEEE Control Systems Letters
- Chief Specialty Editor for Mechatronics, Frontiers in Mechanical Engineering (Nature Publishing Group)
- IEEE Nanotechnology Council – Control Systems Society Representative
- Awards Committees
- 2020 IEEE Control Systems Society Outstanding Paper Award
- 2019 IEEE Conference on Decision and Control (CDC2019) – Best Student Paper Award
- International Program Committee Member for the following conferences:
- 2020 IFAC World Congress
- 2020 IEEE Conference on Control Technology and Applications (CCTA2020)
- 2020 Sustainable Design and Manufacturing (KES-SDM-20)
- 2020 IEEE International Workshop on Advanced Motion Control (AMC2020)
- 2019 IEEE Conference on Control Technology and Applications (CCTA)
- 2019 IFAC Symposium on Mechatronic Systems and IFAC Symposium on Nonlinear Control
- 2019 International Conference on Sustainable Design and Manufacturing (KES-SDM-19)
- 2018 International Conference on Sustainable Design and Manufacturing (KES-SDM-18)
- 2015 American Control Conference, Chicago, IL, 2015
- 2014 American Control Conference, Portland, OR, 2014
- 2013 American Control Conference, Vancouver, 2013
- 2004 3rd IFAC Symposium on Mechatronic Systems, Sydney, 2004
- Associate editor: Advances in Vibration and Acoustics (2007‐2011)
Research Impact
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- 200 Publications, 77 Journal Articles, 102 Conference Articles, 3 Books
- 5500 Citations, H‐Index: 41 (Google Scholar)
- 9 Patent Applications, international licensing in 13 countries
- Consulting: NASA, DSTO, US Army, Nikon, Stanford Accelerator Lab, GE Medical etc.
Publications
2021 |
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| 213. |  | M. G. Ruppert; A. J. Fleming; Y. K. Yong Active atomic force microscope cantilevers with integrated device layer piezoresistive sensors Journal Article Sensors & Actuators: A. Physical, 2021. @article{Ruppert2021, title = {Active atomic force microscope cantilevers with integrated device layer piezoresistive sensors}, author = {M. G. Ruppert and A. J. Fleming and Y. K. Yong}, doi = {10.1016/j.sna.2020.112519}, year = {2021}, date = {2021-01-19}, journal = {Sensors & Actuators: A. Physical}, abstract = {Active atomic force microscope cantilevers with on-chip actuation and sensing provide several advantages over passive cantilevers which rely on piezoacoustic base-excitation and optical beam deflection measurement. Active microcantilevers exhibit a clean frequency response, provide a path-way to miniturization and parallelization and avoid the need for optical alignment. However, active microcantilevers are presently limited by the feedthrough between actuators and sensors, and by the cost associated with custom microfabrication. In this work, we propose a hybrid cantilever design with integrated piezoelectric actuators and a piezoresistive sensor fabricated from the silicon device layer without requiring an additional doping step. As a result, the design can be fabricated using a commercial five-mask microelectromechanical systems fabrication process. The theoretical piezoresistor sensitivity is compared with finite element simulations and experimental results obtained from a prototype device. The proposed approach is demonstrated to be a promising alternative to conventional microcantilever actuation and deflection sensing}, keywords = {}, pubstate = {published}, tppubtype = {article} } Active atomic force microscope cantilevers with on-chip actuation and sensing provide several advantages over passive cantilevers which rely on piezoacoustic base-excitation and optical beam deflection measurement. Active microcantilevers exhibit a clean frequency response, provide a path-way to miniturization and parallelization and avoid the need for optical alignment. However, active microcantilevers are presently limited by the feedthrough between actuators and sensors, and by the cost associated with custom microfabrication. In this work, we propose a hybrid cantilever design with integrated piezoelectric actuators and a piezoresistive sensor fabricated from the silicon device layer without requiring an additional doping step. As a result, the design can be fabricated using a commercial five-mask microelectromechanical systems fabrication process. The theoretical piezoresistor sensitivity is compared with finite element simulations and experimental results obtained from a prototype device. The proposed approach is demonstrated to be a promising alternative to conventional microcantilever actuation and deflection sensing |
2020 |
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| 212. |  | M. S. Xavier; A. J. Fleming; Y. K. Yong Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments Journal Article Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments, pp. 2000187, 2020. @article{Xavier2020, title = {Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments}, author = {M. S. Xavier and A. J. Fleming and Y. K. Yong}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aisy.202000187http://www.precisionmechatronicslab.com/wp-content/uploads/2020/10/document.pdf}, doi = {10.1002/aisy.202000187}, year = {2020}, date = {2020-10-30}, journal = {Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments}, pages = {2000187}, abstract = {Many soft robots are composed of soft fluidic actuators that are fabricated from silicone rubbers and use hydraulic or pneumatic actuation. The strong nonlinearities and complex geometries of soft actuators hinder the development of analytical models to describe their motion. Finite element modeling provides an effective solution to this issue and allows the user to predict performance and optimize soft actuator designs. Herein, the literature on a finite element analysis of soft actuators is reviewed. First, the required nonlinear elasticity concepts are introduced with a focus on the relevant models for soft robotics. In particular, the procedure for determining material constants for the hyperelastic models from material testing and curve fitting is explored. Then, a comprehensive review of constitutive model parameters for the most widely used silicone rubbers in the literature is provided. An overview of the procedure is provided for three commercially available software packages (Abaqus, Ansys, and COMSOL). The combination of modeling procedures, material properties, and design guidelines presented in this article can be used as a starting point for soft robotic actuator design.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Many soft robots are composed of soft fluidic actuators that are fabricated from silicone rubbers and use hydraulic or pneumatic actuation. The strong nonlinearities and complex geometries of soft actuators hinder the development of analytical models to describe their motion. Finite element modeling provides an effective solution to this issue and allows the user to predict performance and optimize soft actuator designs. Herein, the literature on a finite element analysis of soft actuators is reviewed. First, the required nonlinear elasticity concepts are introduced with a focus on the relevant models for soft robotics. In particular, the procedure for determining material constants for the hyperelastic models from material testing and curve fitting is explored. Then, a comprehensive review of constitutive model parameters for the most widely used silicone rubbers in the literature is provided. An overview of the procedure is provided for three commercially available software packages (Abaqus, Ansys, and COMSOL). The combination of modeling procedures, material properties, and design guidelines presented in this article can be used as a starting point for soft robotic actuator design. |
| 211. |  | M. G. Ruppert; D. M. Harcombe; A. J. Fleming Traditional and Novel Demodulators for Multifrequency Atomic Force Microscopy Conference 8th Multifrequency AFM Conference, Madrid, Spain, 2020. @conference{Ruppert2020b, title = {Traditional and Novel Demodulators for Multifrequency Atomic Force Microscopy}, author = {M. G. Ruppert and D. M. Harcombe and A. J. Fleming}, year = {2020}, date = {2020-10-27}, booktitle = {8th Multifrequency AFM Conference}, address = {Madrid, Spain}, abstract = {A number of multifrequency atomic force microscopy (MF-AFM) methods make use of the excitation and detection of higher harmonics of the fundamental frequency, higher flexural eigenmodes or intermodulation products generated by the non-linear tip-sample force [1]. Schematically, these methods are depicted in Figure 1(a) where the main difference is the resulting spacing and amplitude of the frequency components in the generated spectrum shown in Figure 1(b). Regardless of which particular MF-AFM method is employed, each requires a demodulator to obtain amplitude and phase to form observables for the characterization of nanomechanical sample information. Since high-speed non-synchronous demodulators such as the peak-hold method, peak detector and RMS-to-DC converter are incompatible with MF-AFM [2], there is a need for high-bandwidth demodulation techniques capable of estimating multiple frequencies at once while maintaining robustness against unwanted frequency components [3]. In this talk, the performance of traditional and recently proposed demodulators for multifrequency atomic force microscopy is assessed experimentally. The compared methods include the lock-in amplifier, coherent demodulator, Kalman filter, Lyapunov filter, and direct-design demodulator. Each method is implemented on a field-programmable gate array (FPGA) with a sampling rate of 1.5 MHz. The metrics for comparison include implementation complexity, the sensitivity to other frequency components and the magnitude of demodulation artifacts for a range of demodulator bandwidths. Performance differences are demonstrated through higher harmonic atomic force microscopy imaging.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } A number of multifrequency atomic force microscopy (MF-AFM) methods make use of the excitation and detection of higher harmonics of the fundamental frequency, higher flexural eigenmodes or intermodulation products generated by the non-linear tip-sample force [1]. Schematically, these methods are depicted in Figure 1(a) where the main difference is the resulting spacing and amplitude of the frequency components in the generated spectrum shown in Figure 1(b). Regardless of which particular MF-AFM method is employed, each requires a demodulator to obtain amplitude and phase to form observables for the characterization of nanomechanical sample information. Since high-speed non-synchronous demodulators such as the peak-hold method, peak detector and RMS-to-DC converter are incompatible with MF-AFM [2], there is a need for high-bandwidth demodulation techniques capable of estimating multiple frequencies at once while maintaining robustness against unwanted frequency components [3]. In this talk, the performance of traditional and recently proposed demodulators for multifrequency atomic force microscopy is assessed experimentally. The compared methods include the lock-in amplifier, coherent demodulator, Kalman filter, Lyapunov filter, and direct-design demodulator. Each method is implemented on a field-programmable gate array (FPGA) with a sampling rate of 1.5 MHz. The metrics for comparison include implementation complexity, the sensitivity to other frequency components and the magnitude of demodulation artifacts for a range of demodulator bandwidths. Performance differences are demonstrated through higher harmonic atomic force microscopy imaging. |
| 210. |  | A. J. Fleming; M. G. Ruppert; B. S. Routley; L. McCourt Overcoming the Limitations of Tip Enhanced Raman Spectroscopy with Intermittent Contact AFM Conference 8th Multifrequency AFM Conference, Madrid, Spain, 2020. @conference{Fleming2020, title = {Overcoming the Limitations of Tip Enhanced Raman Spectroscopy with Intermittent Contact AFM}, author = {A. J. Fleming and M. G. Ruppert and B. S. Routley and L. McCourt}, year = {2020}, date = {2020-10-27}, booktitle = {8th Multifrequency AFM Conference}, address = {Madrid, Spain}, abstract = {Tip enhanced Raman spectroscopy (TERS) is a promising technique for mapping the chemical composition of surfaces with molecular scale. However, current TERS methods are limited by a number of issues including high tip-sample forces, high laser power, low topographical resolution, and short probe lifetime. As a result, TERS methods are best suited to robust samples that can tolerate high optical intensity. To overcome these issues and extend the application of TERS to delicate samples, a number of new probes andimaging modes are in development at the University of Newcastle. This talk will provide an overview of these methods and present preliminary results, including new methods for optical probe optimization and fabrication, and a new dynamic-mode AFM method to reduce contact forces and applied laser power.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Tip enhanced Raman spectroscopy (TERS) is a promising technique for mapping the chemical composition of surfaces with molecular scale. However, current TERS methods are limited by a number of issues including high tip-sample forces, high laser power, low topographical resolution, and short probe lifetime. As a result, TERS methods are best suited to robust samples that can tolerate high optical intensity. To overcome these issues and extend the application of TERS to delicate samples, a number of new probes andimaging modes are in development at the University of Newcastle. This talk will provide an overview of these methods and present preliminary results, including new methods for optical probe optimization and fabrication, and a new dynamic-mode AFM method to reduce contact forces and applied laser power. |
| 209. |  | L. McCourt; M. G. Ruppert; B. S. Routley; S. Indirathankam; A. J. Fleming A comparison of gold and silver nanocones and geometry optimisation for tip-enhanced microscopy Journal Article Journal of Raman Spectroscopy, pp. 1-9, 2020. @article{McCourt2020, title = {A comparison of gold and silver nanocones and geometry optimisation for tip-enhanced microscopy}, author = {L. McCourt and M. G. Ruppert and B. S. Routley and S. Indirathankam and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/09/J20e.pdf}, doi = {https://doi.org/10.1002/jrs.5987}, year = {2020}, date = {2020-08-24}, journal = {Journal of Raman Spectroscopy}, pages = {1-9}, abstract = {In this article, boundary element method simulations are used to optimise the geometry of silver and gold nanocone probes to maximise the localised electric field enhancement and tune the near-field resonance wavelength. These objectives are expected to maximise the sensitivity of tip-enhanced Raman microscopes. Similar studies have used limited parameter sets or used a performance metric other than localised electric field enhancement. In this article, the optical responses for a range of nanocone geometries are simulated for excitation wavelengths ranging from 400 to 1000 nm. Performance is evaluated by measuring the electric field enhancement at the sample surface with a resonant illumination wavelength. These results are then used to determine empirical models and derive optimal nanocone geometries for a particular illumination wavelength and tip material. This article concludes that gold nanocones are expected to provide similar performance to silver nanocones at red and nearinfrared wavelengths, which is consistent with other results in the literature. In this article, 633 nm is determined to be the shortest usable illumination wavelength for gold nanocones. Below this limit, silver nanocones will provide superior enhancement. The use of gold nanocone probes is expected to dramatically improve probe lifetime, which is currently measured in hours for silver coated probes. Furthermore, the elimination of passivation coatings is expected to enable smaller probe radii and improved topographical resolution.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this article, boundary element method simulations are used to optimise the geometry of silver and gold nanocone probes to maximise the localised electric field enhancement and tune the near-field resonance wavelength. These objectives are expected to maximise the sensitivity of tip-enhanced Raman microscopes. Similar studies have used limited parameter sets or used a performance metric other than localised electric field enhancement. In this article, the optical responses for a range of nanocone geometries are simulated for excitation wavelengths ranging from 400 to 1000 nm. Performance is evaluated by measuring the electric field enhancement at the sample surface with a resonant illumination wavelength. These results are then used to determine empirical models and derive optimal nanocone geometries for a particular illumination wavelength and tip material. This article concludes that gold nanocones are expected to provide similar performance to silver nanocones at red and nearinfrared wavelengths, which is consistent with other results in the literature. In this article, 633 nm is determined to be the shortest usable illumination wavelength for gold nanocones. Below this limit, silver nanocones will provide superior enhancement. The use of gold nanocone probes is expected to dramatically improve probe lifetime, which is currently measured in hours for silver coated probes. Furthermore, the elimination of passivation coatings is expected to enable smaller probe radii and improved topographical resolution. |
| 208. |  | M. Omidbeike; Y. K. Yong; A. J. Fleming Sensing and Decentralized Control of a Five-Axis Monolithic Nanopositioning Stage Inproceedings IFAC World Congress, 2020. @inproceedings{C20a, title = {Sensing and Decentralized Control of a Five-Axis Monolithic Nanopositioning Stage}, author = {M. Omidbeike and Y. K. Yong and A. J. Fleming}, year = {2020}, date = {2020-07-11}, booktitle = {IFAC World Congress}, abstract = {This article describes the design and calibration of a five degree-of-freedom linearand angular displacement sensor utilizing piezoresistive strain gages. A simple decentralized controller is then implemented to follow linear and angular reference signals. The foremost difficulty with piezoresistive sensors is their high-temperature sensitivity. In addition, they are sensitive to motion in multiple degrees of freedom, which must be decoupled before use as a displacement sensor. A new sensing design is proposed which provides decoupled measurements of linear and angular displacements in multi-axis monolithic nanopositioning stages. The proposed method employs system identification and feedforward techniques to calibrate each axis and minimize cross-coupling. }, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This article describes the design and calibration of a five degree-of-freedom linearand angular displacement sensor utilizing piezoresistive strain gages. A simple decentralized controller is then implemented to follow linear and angular reference signals. The foremost difficulty with piezoresistive sensors is their high-temperature sensitivity. In addition, they are sensitive to motion in multiple degrees of freedom, which must be decoupled before use as a displacement sensor. A new sensing design is proposed which provides decoupled measurements of linear and angular displacements in multi-axis monolithic nanopositioning stages. The proposed method employs system identification and feedforward techniques to calibrate each axis and minimize cross-coupling. |
| 207. |  | M. S. Xavier; A. J. Fleming; Y. K. Yong Modelling and Simulation of Pneumatic Sources for Soft Robotic Applications Inproceedings IEEE/ASME International Conference on Advanced Intelligent Mechatronics, Boston, MA, 2020. @inproceedings{C20b, title = {Modelling and Simulation of Pneumatic Sources for Soft Robotic Applications}, author = {M. S. Xavier and A. J. Fleming and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/09/AIM2020_Published.pdf}, doi = {10.1109/aim43001.2020.9158802}, year = {2020}, date = {2020-07-01}, booktitle = {IEEE/ASME International Conference on Advanced Intelligent Mechatronics}, address = {Boston, MA}, abstract = {The mathematical models for two widely used pneumatic systems in the soft robotics community are presented: syringe pumps and compressed air systems. These models enable prediction and optimisation of performance of soft actuators under pressurisation, allowing the user to select pneumatic components for a desired behaviour. Analytical models are confirmed with simulations developed using SimScape Fluids and SimScape Electrical within Simulink/MATLAB. By using a polytropic law, the models show agreement with the simulations with less than 10% discrepancy for the typical pressures used with soft actuators. Syringe pumps are shown to be much slower compared to the compressed air systems. In the latter, the addition of an air receiver allows very short actuation time.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } The mathematical models for two widely used pneumatic systems in the soft robotics community are presented: syringe pumps and compressed air systems. These models enable prediction and optimisation of performance of soft actuators under pressurisation, allowing the user to select pneumatic components for a desired behaviour. Analytical models are confirmed with simulations developed using SimScape Fluids and SimScape Electrical within Simulink/MATLAB. By using a polytropic law, the models show agreement with the simulations with less than 10% discrepancy for the typical pressures used with soft actuators. Syringe pumps are shown to be much slower compared to the compressed air systems. In the latter, the addition of an air receiver allows very short actuation time. |
| 206. |  | D. S. Raghunvanshi; S. I. Moore; A. J. Fleming; Y. K. Yong Electrode Configurations for Piezoelectric Tube Actuators With Improved Scan Range and Reduced Cross-Coupling Journal Article IEEE/ASME Transactions on Mechatronics, 25 (3), pp. 1479-1486, 2020, ISSN: 00346748. @article{J20d, title = {Electrode Configurations for Piezoelectric Tube Actuators With Improved Scan Range and Reduced Cross-Coupling}, author = {D. S. Raghunvanshi and S. I. Moore and A. J. Fleming and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/09/J20d.pdf}, doi = {10.1109/TMECH.2020.2978241}, issn = {00346748}, year = {2020}, date = {2020-06-01}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {25}, number = {3}, pages = {1479-1486}, abstract = {Piezoelectric force and position sensors provide high sensitivity but are limited at low frequencies due to their high-pass response which complicates the direct application of integral control. To overcome this issue, an additional sensor or low-frequency correction method is typically employed. However, these approaches introduce an additional first-order response that must be higher than the high-pass response of the piezo and interface electronics. This article describes a simplified method for low-frequency correction that uses the piezoelectric sensor as an electrical component in a filter circuit. The resulting response is first-order, rather than second-order, with a cut-off frequency equal to that of a buffer circuit with the same input resistance. The proposed method is demonstrated to allow simultaneous damping and tracking control of a high-speed vertical nanopositioning stage.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Piezoelectric force and position sensors provide high sensitivity but are limited at low frequencies due to their high-pass response which complicates the direct application of integral control. To overcome this issue, an additional sensor or low-frequency correction method is typically employed. However, these approaches introduce an additional first-order response that must be higher than the high-pass response of the piezo and interface electronics. This article describes a simplified method for low-frequency correction that uses the piezoelectric sensor as an electrical component in a filter circuit. The resulting response is first-order, rather than second-order, with a cut-off frequency equal to that of a buffer circuit with the same input resistance. The proposed method is demonstrated to allow simultaneous damping and tracking control of a high-speed vertical nanopositioning stage. |
| 205. |  | M. G. Ruppert; N. J. Bartlett; Y. K. Yong; A. J. Fleming Amplitude Noise Spectrum of a Lock-in Amplifier: Application to Microcantilever Noise Measurements Journal Article Sensors and Actuators A: Physical, 312 , pp. 112092, 2020. @article{Ruppert2020, title = {Amplitude Noise Spectrum of a Lock-in Amplifier: Application to Microcantilever Noise Measurements}, author = {M. G. Ruppert and N. J. Bartlett and Y. K. Yong and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/09/J20f.pdf}, doi = {10.1016/j.sna.2020.112092}, year = {2020}, date = {2020-05-29}, journal = {Sensors and Actuators A: Physical}, volume = {312}, pages = {112092}, abstract = {The lock-in amplifier is a crucial component in many applications requiring high-resolution displacement sensing; it's purpose is to estimate the amplitude and phase of a periodic signal, potentially corrupted by noise, at a frequency determined by a reference signal. Where the noise can be approximated by a stationary Gaussian process, such as thermal force noise and electronic sensor noise, this article derives the amplitude noise spectral density of the lock-in-amplifier output. The proposed method is demonstrated by predicting the demodulated noise spectrum of a microcantilever for dynamic-mode atomic force microscopy to determine the cantilever on-resonance thermal noise, the cantilever tracking bandwidth and the electronic noise floor. The estimates are shown to closely match experimental results over a wide range of operating conditions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The lock-in amplifier is a crucial component in many applications requiring high-resolution displacement sensing; it's purpose is to estimate the amplitude and phase of a periodic signal, potentially corrupted by noise, at a frequency determined by a reference signal. Where the noise can be approximated by a stationary Gaussian process, such as thermal force noise and electronic sensor noise, this article derives the amplitude noise spectral density of the lock-in-amplifier output. The proposed method is demonstrated by predicting the demodulated noise spectrum of a microcantilever for dynamic-mode atomic force microscopy to determine the cantilever on-resonance thermal noise, the cantilever tracking bandwidth and the electronic noise floor. The estimates are shown to closely match experimental results over a wide range of operating conditions. |
| 204. |  | A. A. Eielsen; J. Leth; A. J. Fleming; A. G. Wills; B. Ninness Large-amplitude Dithering Mitigates Glitches in Digital-to-analogue Converters Journal Article IEEE Transactions on Signal Processing, 68 , pp. 1950-1963, 2020, ISSN: 19410476. @article{J20c, title = {Large-amplitude Dithering Mitigates Glitches in Digital-to-analogue Converters}, author = {A. A. Eielsen and J. Leth and A. J. Fleming and A. G. Wills and B. Ninness}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/06/J20c.pdf}, doi = {10.1109/TSP.2020.2978626}, issn = {19410476}, year = {2020}, date = {2020-04-01}, journal = {IEEE Transactions on Signal Processing}, volume = {68}, pages = {1950-1963}, abstract = {Glitches introduce impulse-like disturbances which are not be readily attenuated by low-pass filtering. This article presents a model that describes the behaviour of glitches, and a method for mitigation based on a large-amplitude dither signal. Analytical and experimental results demonstrate that a dither signal with sufficient amplitude can mitigate the effect of glitches, when used in conjunction with a low-pass filter. The dither signal in conjunction with low-pass filtering essentially converts a glitch from a high-frequency to low-frequency disturbance.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Glitches introduce impulse-like disturbances which are not be readily attenuated by low-pass filtering. This article presents a model that describes the behaviour of glitches, and a method for mitigation based on a large-amplitude dither signal. Analytical and experimental results demonstrate that a dither signal with sufficient amplitude can mitigate the effect of glitches, when used in conjunction with a low-pass filter. The dither signal in conjunction with low-pass filtering essentially converts a glitch from a high-frequency to low-frequency disturbance. |
| 203. |  | D. M. Harcombe; M. G. Ruppert; A. J. Fleming A review of demodulation techniques for multifrequency atomic force microscopy Journal Article Beilstein Journal of Nanotechnology, 11 , pp. 76-97, 2020, ISSN: 21904286. @article{Harcombe2020, title = {A review of demodulation techniques for multifrequency atomic force microscopy}, author = {D. M. Harcombe and M. G. Ruppert and A. J. Fleming}, editor = {T. Glatzel}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/02/J20b-reducedSize.pdf}, doi = {doi:10.3762/bjnano.11.8}, issn = {21904286}, year = {2020}, date = {2020-01-07}, journal = {Beilstein Journal of Nanotechnology}, volume = {11}, pages = {76-97}, abstract = {This article compares the performance of traditional and recently proposed demodulators for multifrequency atomic force microscopy. The compared methods include the lock-in amplifier, coherent demodulator, Kalman filter, Lyapunov filter, and direct-design demodulator. Each method is implemented on a field-programmable gate array (FPGA) with a sampling rate of 1.5 MHz. The metrics for comparison include the sensitivity to other frequency components and the magnitude of demodulation artifacts for a range of demodulator bandwidths. Performance differences are demonstrated through higher harmonic atomic force microscopy imaging.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article compares the performance of traditional and recently proposed demodulators for multifrequency atomic force microscopy. The compared methods include the lock-in amplifier, coherent demodulator, Kalman filter, Lyapunov filter, and direct-design demodulator. Each method is implemented on a field-programmable gate array (FPGA) with a sampling rate of 1.5 MHz. The metrics for comparison include the sensitivity to other frequency components and the magnitude of demodulation artifacts for a range of demodulator bandwidths. Performance differences are demonstrated through higher harmonic atomic force microscopy imaging. |
| 202. |  | R. Rozario; A. J. Fleming; T. Oomen Finite-Time Learning Control Using Frequency Response Data with Application to a Nanopositioning Stage Journal Article IEEE/ASME Transactions on Mechatronics, 24 (5), pp. 2085-2096, 2020, ISSN: 10834435. @article{J20a, title = {Finite-Time Learning Control Using Frequency Response Data with Application to a Nanopositioning Stage}, author = {R. Rozario and A. J. Fleming and T. Oomen}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/09/J20a-1.pdf}, doi = {10.1109/TMECH.2019.2931407}, issn = {10834435}, year = {2020}, date = {2020-01-01}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {24}, number = {5}, pages = {2085-2096}, abstract = {Learning control enables significant performance improvement for systems that perform repeating tasks. Achieving high tracking performance by utilizing past error data typically requires noncausal learning that is based on a parametric model of the process. Such model-based approaches impose significant requirements on modeling and filter design. This paper aims to reduce these requirements by developing a learning control framework that enables performance improvement through noncausal learning without relying on a parametric model. This is achieved by explicitly using the discrete Fourier transform to enable learning by using a nonparametric frequency response function model of the process. The effectiveness of the developed method is illustrated by application to a nanopositioning stage}, keywords = {}, pubstate = {published}, tppubtype = {article} } Learning control enables significant performance improvement for systems that perform repeating tasks. Achieving high tracking performance by utilizing past error data typically requires noncausal learning that is based on a parametric model of the process. Such model-based approaches impose significant requirements on modeling and filter design. This paper aims to reduce these requirements by developing a learning control framework that enables performance improvement through noncausal learning without relying on a parametric model. This is achieved by explicitly using the discrete Fourier transform to enable learning by using a nonparametric frequency response function model of the process. The effectiveness of the developed method is illustrated by application to a nanopositioning stage |
2019 |
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| 201. |  | M. S. Xavier; A. J. Fleming; Y. K. Yong Image-Guided Locomotion of a Pneumatic-Driven Peristaltic Soft Robot Inproceedings IEEE International Conference on Robotics and Biomimetics, Dali, Yunnan, China, 2019, ISBN: 1-4244-0570-X. @inproceedings{C19h, title = {Image-Guided Locomotion of a Pneumatic-Driven Peristaltic Soft Robot}, author = {M. S. Xavier and A. J. Fleming and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/09/C19h.pdf}, doi = {10.1109/ROBIO49542.2019.8961406}, isbn = {1-4244-0570-X}, year = {2019}, date = {2019-12-06}, booktitle = {IEEE International Conference on Robotics and Biomimetics}, address = {Dali, Yunnan, China}, abstract = {In this work, a pneumatic-driven peristaltic soft robot with pressure feedback control and image-guided tracking is developed. Locomotion is achieved in tube-like environments by mimicking the peristaltic motion of earthworms. The soft actuators are made of silicone rubber with 3D molding and fiber reinforcements. Pressure control is performed using custom made syringe pumps and on/off controllers in Arduino. Realtime visual tracking is accomplished in OpenCV with a colorbased approach. The soft robot has a stroke of 30-35mm for each cycle of actuation. This pneumatic soft robot shows great potential for application in minimally invasive surgery due to its compliance and biocompatibility.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } In this work, a pneumatic-driven peristaltic soft robot with pressure feedback control and image-guided tracking is developed. Locomotion is achieved in tube-like environments by mimicking the peristaltic motion of earthworms. The soft actuators are made of silicone rubber with 3D molding and fiber reinforcements. Pressure control is performed using custom made syringe pumps and on/off controllers in Arduino. Realtime visual tracking is accomplished in OpenCV with a colorbased approach. The soft robot has a stroke of 30-35mm for each cycle of actuation. This pneumatic soft robot shows great potential for application in minimally invasive surgery due to its compliance and biocompatibility. |
| 200. |  | M. G. Ruppert; N. F. S. D. Bem; A. J. Fleming; Y. K. Yong Characterization of Active Microcantilevers Using Laser Doppler Vibrometry Inproceedings 18th Asian Pacific Vibration Conference, Sydney, Australia, 2019. @inproceedings{Ruppert2019b, title = {Characterization of Active Microcantilevers Using Laser Doppler Vibrometry}, author = {M. G. Ruppert and N. F. S. D. Bem and A. J. Fleming and Y. K. Yong}, year = {2019}, date = {2019-11-18}, booktitle = {18th Asian Pacific Vibration Conference}, address = {Sydney, Australia}, abstract = {Active atomic force microscope cantilevers with on-chip actuation and sensing provide several advantages over passive cantilevers which rely on piezoacoustic base-excitation and the optical beam deflection measurement. Most importantly, these cantilevers provide clean frequency responses, the possibility of down-scaling and parallelization to cantilever arrays as well as the absence of optical interferences. In this paper, we demonstrate the analysis and calibration steps for three active cantilever geometries with integrated piezoelectric actuation. For this purpose, laser Doppler vibrometry (LDV) is used to experimentally obtain the deflection mode shapes of the first three eigenmodes, calibrate actuation gains, and to determine the dynamic modal stiffnesses using the Brownian spectrum of the cantilever. The experimental values are compared with finite element simulations.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Active atomic force microscope cantilevers with on-chip actuation and sensing provide several advantages over passive cantilevers which rely on piezoacoustic base-excitation and the optical beam deflection measurement. Most importantly, these cantilevers provide clean frequency responses, the possibility of down-scaling and parallelization to cantilever arrays as well as the absence of optical interferences. In this paper, we demonstrate the analysis and calibration steps for three active cantilever geometries with integrated piezoelectric actuation. For this purpose, laser Doppler vibrometry (LDV) is used to experimentally obtain the deflection mode shapes of the first three eigenmodes, calibrate actuation gains, and to determine the dynamic modal stiffnesses using the Brownian spectrum of the cantilever. The experimental values are compared with finite element simulations. |
| 199. |  | M. S. Xavier; A. J. Fleming; Y. K. Yong Experimental Characterisation of Hydraulic Fiber-Reinforced Soft Actuators for Worm-Like Robots Inproceedings International Conference on Control, Mechatronics and Automation, Delft, Netherlands, 2019, ISBN: 978-1-7281-3787-2. @inproceedings{C19g, title = {Experimental Characterisation of Hydraulic Fiber-Reinforced Soft Actuators for Worm-Like Robots}, author = {M. S. Xavier and A. J. Fleming and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/05/C19g-reduced.pdf}, doi = {10.1109/ICCMA46720.2019.8988691}, isbn = {978-1-7281-3787-2}, year = {2019}, date = {2019-11-06}, booktitle = {International Conference on Control, Mechatronics and Automation}, address = {Delft, Netherlands}, abstract = {This article describes the design and fabrication of fiber-reinforced soft actuators for a snake-like robot designed to operate inside constrained tubes. The actuators include bending, extension and torsion. These actuators were experimentally characterised using water as the driving fluid with the aid of a water pressure sensor connected to Arduino and video recordings. It is shown that fiber wrapping, geometry of cross-section and elastomer selection are the main parameters affecting the levels of extension, bending and torsion of these actuators. Then, multi-material soft actuators are developed and used to present a soft robot capable of crawling a pipe, a mechanism that could be explored in steerable catheters,endoscopes and pipe inspection devices.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This article describes the design and fabrication of fiber-reinforced soft actuators for a snake-like robot designed to operate inside constrained tubes. The actuators include bending, extension and torsion. These actuators were experimentally characterised using water as the driving fluid with the aid of a water pressure sensor connected to Arduino and video recordings. It is shown that fiber wrapping, geometry of cross-section and elastomer selection are the main parameters affecting the levels of extension, bending and torsion of these actuators. Then, multi-material soft actuators are developed and used to present a soft robot capable of crawling a pipe, a mechanism that could be explored in steerable catheters,endoscopes and pipe inspection devices. |
| 198. |  | S. I. Moore; A. J. Fleming; Y. K. Yong Capacitive Instrumentation and Sensor Fusion for High-Bandwidth Nanopositioning Journal Article IEEE Sensor Letters, 3 (8), pp. 2501503, 2019, ISBN: 2475-1472. @article{Moore2019, title = {Capacitive Instrumentation and Sensor Fusion for High-Bandwidth Nanopositioning}, author = {S. I. Moore and A. J. Fleming and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2019/10/J19c.pdf}, doi = {10.1109/LSENS.2019.2933065}, isbn = {2475-1472}, year = {2019}, date = {2019-09-09}, journal = {IEEE Sensor Letters}, volume = {3}, number = {8}, pages = {2501503}, abstract = {Precision capacitive sensing methods encode the measurement in a high frequency signal, which requires demodulation. To extract the measurement, the signal is observed over many cycles limiting the bandwidth of the sensor and introducing an undesirable phase lag. To address this limitation, this article outlines a design, which fuses the output of a standard modulated capacitive sensor and a charge amplifier, providing an instantaneous capacitive measurement whose bandwidth is only limited by the speed at which the electronics operate.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Precision capacitive sensing methods encode the measurement in a high frequency signal, which requires demodulation. To extract the measurement, the signal is observed over many cycles limiting the bandwidth of the sensor and introducing an undesirable phase lag. To address this limitation, this article outlines a design, which fuses the output of a standard modulated capacitive sensor and a charge amplifier, providing an instantaneous capacitive measurement whose bandwidth is only limited by the speed at which the electronics operate. |
| 197. |  | L. McCourt; B. S. Routley; M. G. Ruppert; A. J. Fleming Resolution and Enhancement of Probes for Tip Enhanced Raman Spectroscopy Conference International Conference on Nanophotonics and Micro/Nano Optics (NANOP), Munich, Germany, 2019. @conference{McCourt2019, title = {Resolution and Enhancement of Probes for Tip Enhanced Raman Spectroscopy}, author = {L. McCourt and B. S. Routley and M. G. Ruppert and A. J. Fleming}, year = {2019}, date = {2019-09-04}, booktitle = {International Conference on Nanophotonics and Micro/Nano Optics (NANOP)}, journal = {International Conference Nanophotonics and Micro/Nano Optics}, address = {Munich, Germany}, abstract = {Two photon apertureless nearfield lithography allows sub diffraction limited features for integrated circuit production. It involves exciting surface plasmons on a metallic atomic force microscopy probe, which generates an enhancement of the localised electric field, exposing a photoresist. Costing less than extreme ultra violet lithography, and reducing exposure from scattered light compared to one photon nearfield lithography, this technique is suited for device prototyping or low volume production. The work here considers the material and geometry of an ideal AFM probe in terms of resolution (producing the smallest features) and electric field enhancement.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Two photon apertureless nearfield lithography allows sub diffraction limited features for integrated circuit production. It involves exciting surface plasmons on a metallic atomic force microscopy probe, which generates an enhancement of the localised electric field, exposing a photoresist. Costing less than extreme ultra violet lithography, and reducing exposure from scattered light compared to one photon nearfield lithography, this technique is suited for device prototyping or low volume production. The work here considers the material and geometry of an ideal AFM probe in terms of resolution (producing the smallest features) and electric field enhancement. |
| 196. |  | A. J. Fleming; O. T. Ghalehbeygi; B. S. Routley; A. G. Wills Scanning Laser Lithography with Constrained Quadratic Exposure Optimization Journal Article IEEE Transactions on Control Systems Technology, 27 (5), pp. 2221-2228, 2019, ISBN: 1063-6536. @article{J19e, title = {Scanning Laser Lithography with Constrained Quadratic Exposure Optimization}, author = {A. J. Fleming and O. T. Ghalehbeygi and B. S. Routley and A. G. Wills}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/02/J19e.pdf}, doi = {10.1109/TCST.2018.2836910}, isbn = {1063-6536}, year = {2019}, date = {2019-09-01}, journal = {IEEE Transactions on Control Systems Technology}, volume = {27}, number = {5}, pages = {2221-2228}, abstract = {Scanning laser lithography is a maskless lithography method for selectively exposing features on a film of photoresist. A set of exposure positions and beam energies are required to optimally reproduce the desired feature pattern. The task of determining the exposure energies is inherently non-linear due to the photoresist model and the requirement for only positive energy. In this article, a nonlinear programming approach is employed to find an optimal exposure profile that minimizes the feature error and total exposure energy. This method is demonstrated experimentally to create a features with sub-wavelength geometry.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Scanning laser lithography is a maskless lithography method for selectively exposing features on a film of photoresist. A set of exposure positions and beam energies are required to optimally reproduce the desired feature pattern. The task of determining the exposure energies is inherently non-linear due to the photoresist model and the requirement for only positive energy. In this article, a nonlinear programming approach is employed to find an optimal exposure profile that minimizes the feature error and total exposure energy. This method is demonstrated experimentally to create a features with sub-wavelength geometry. |
| 195. |  | S. I. Moore; M. G. Ruppert; D. M. Harcombe; A. J. Fleming; Y. K. Yong Design and Analysis of Low-Distortion Demodulators for Modulated Sensors Journal Article IEEE/ASME Transactions on Mechatronics, 24 (4), pp. 1861-1870, 2019, ISSN: 10834435. @article{Moore2019, title = {Design and Analysis of Low-Distortion Demodulators for Modulated Sensors}, author = { S. I. Moore and M. G. Ruppert and D. M. Harcombe and A. J. Fleming and Y. K. Yong }, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/05/J19d-reduced.pdf}, doi = {10.1109/TMECH.2019.2928592}, issn = {10834435}, year = {2019}, date = {2019-07-17}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {24}, number = {4}, pages = {1861-1870}, abstract = {System-based demodulators in the form of a Kalman and Lyapunov filter have been demonstrated to significantly outperform traditional demodulators, such as the lock-in amplifier, in bandwidth sensitive applications, for example high-speed atomic force microscopy. Building on their closed loop architecture, this article describes a broader class of high-speed closed-loop demodulators. The generic structure provides greater flexibility to independently control the bandwidth and sensitivity to out-of-band frequencies. A linear time-invariant description is derived which allows the utilization of linear control theory to design the demodulator. Experimental results on a nanopositioner with capacitive sensors demonstrate the realization of arbitrary demodulator dynamics while achieving excellent noise rejection.}, keywords = {}, pubstate = {published}, tppubtype = {article} } System-based demodulators in the form of a Kalman and Lyapunov filter have been demonstrated to significantly outperform traditional demodulators, such as the lock-in amplifier, in bandwidth sensitive applications, for example high-speed atomic force microscopy. Building on their closed loop architecture, this article describes a broader class of high-speed closed-loop demodulators. The generic structure provides greater flexibility to independently control the bandwidth and sensitivity to out-of-band frequencies. A linear time-invariant description is derived which allows the utilization of linear control theory to design the demodulator. Experimental results on a nanopositioner with capacitive sensors demonstrate the realization of arbitrary demodulator dynamics while achieving excellent noise rejection. |
| 194. |  | M. Omidbeike; A. A. Eielsen; Y. K. Yong; A. J. Fleming Multivariable Model-less Feedforward Control of a Monolithic Nanopositioning Stage With FIR Filter Inversion Inproceedings International Conference on Manipulation, Automation and Robotics at Small Scales (MARSS), Helsinki, Finland, 2019. @inproceedings{C19d, title = {Multivariable Model-less Feedforward Control of a Monolithic Nanopositioning Stage With FIR Filter Inversion}, author = {M. Omidbeike and A. A. Eielsen and Y. K. Yong and A. J. Fleming }, year = {2019}, date = {2019-07-02}, booktitle = {International Conference on Manipulation, Automation and Robotics at Small Scales (MARSS)}, address = {Helsinki, Finland}, abstract = {A model-less approach for inversion of the dynamics of multivariable systems using FIR filters is described. Inversion-based feedforward techniques have been widely used in the literature to achieve high-performance output tracking. The foremost difficulties associated with plant inversions are model uncertainties and non-minimum phase zeros. Various model-based methods have been proposed to exclude nonminimum phase zeros when inverting both single-input and single-output (SISO), and multiple-input and multiple-output (MIMO) systems. However, these methods increase the model uncertainty as they are no longer exact. To overcome these difficulties a model-less approach using FIR filters is presented. The results when applying the feedforward FIR filter to a multivariable nanopositioning system is presented, and they demonstrate the effectiveness of the feedforward technique in reducing the cross-coupling and achieving significantly improved output tracking.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A model-less approach for inversion of the dynamics of multivariable systems using FIR filters is described. Inversion-based feedforward techniques have been widely used in the literature to achieve high-performance output tracking. The foremost difficulties associated with plant inversions are model uncertainties and non-minimum phase zeros. Various model-based methods have been proposed to exclude nonminimum phase zeros when inverting both single-input and single-output (SISO), and multiple-input and multiple-output (MIMO) systems. However, these methods increase the model uncertainty as they are no longer exact. To overcome these difficulties a model-less approach using FIR filters is presented. The results when applying the feedforward FIR filter to a multivariable nanopositioning system is presented, and they demonstrate the effectiveness of the feedforward technique in reducing the cross-coupling and achieving significantly improved output tracking. |
| 193. |  | M. Omidbeike; Y. K. Yong; S. I. Moore; A. J. Fleming A Five-Axis Monolithic Nanopositioning Stage Constructed from a Bimorph Piezoelectric Sheet Inproceedings Helsinki, Finland, 2019. @inproceedings{omidbeike2019axis}, title = {A Five-Axis Monolithic Nanopositioning Stage Constructed from a Bimorph Piezoelectric Sheet}, author = {M. Omidbeike and Y. K. Yong and S. I. Moore and A. J. Fleming }, year = {2019}, date = {2019-07-02}, journal = {Int. Conference on Manipulation, Automation and Robotics at Small Scales (MARSS)}, address = {Helsinki, Finland}, abstract = {The paper describes design, modeling and control of a five-axis monolithic nanopositioning stage constructed from a bimorph piezoelectric sheet. In this design, actuators are created by removing parts of the sheet using ultrasonic machining. The constructed nanopositioner is ultra-compact with a thickness of 1 mm. It has a X and Y travel range of 15.5 µm and 13.2 µm respectively; a Z travel range of 26 µm; and a rotational motion about the X-and Y-axis of 600 µrad and 884 µrad respectively. The first resonance frequency occurs at 883 Hz in the Z-axis, and the second and third resonance frequency appears at 1850 Hz, rotating about the X-and Y-axis. A decentralized control strategy is implemented to track Z, θx and θy motions. The controller provides good tracking and significantly reduces cross-coupling motions among the three degrees-of-freedom.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } The paper describes design, modeling and control of a five-axis monolithic nanopositioning stage constructed from a bimorph piezoelectric sheet. In this design, actuators are created by removing parts of the sheet using ultrasonic machining. The constructed nanopositioner is ultra-compact with a thickness of 1 mm. It has a X and Y travel range of 15.5 µm and 13.2 µm respectively; a Z travel range of 26 µm; and a rotational motion about the X-and Y-axis of 600 µrad and 884 µrad respectively. The first resonance frequency occurs at 883 Hz in the Z-axis, and the second and third resonance frequency appears at 1850 Hz, rotating about the X-and Y-axis. A decentralized control strategy is implemented to track Z, θx and θy motions. The controller provides good tracking and significantly reduces cross-coupling motions among the three degrees-of-freedom. |
| 192. |  | M. G. Ruppert; B. S. Routley; A. J. Fleming; Y. K. Yong; G. E. Fantner Model-based Q Factor Control for Photothermally Excited Microcantilevers Inproceedings Int. Conference on Manipulation, Automation and Robotics at Small Scales (MARSS), Helsinki, Finland, 2019. @inproceedings{Ruppert2019, title = {Model-based Q Factor Control for Photothermally Excited Microcantilevers}, author = {M. G. Ruppert and B. S. Routley and A. J. Fleming and Y. K. Yong and G. E. Fantner}, year = {2019}, date = {2019-07-01}, booktitle = {Int. Conference on Manipulation, Automation and Robotics at Small Scales (MARSS)}, address = {Helsinki, Finland}, abstract = {Photothermal excitation of the cantilever for dynamic atomic force microscopy (AFM) modes is an attractive actuation method as it provides clean cantilever actuation leading to well-defined frequency responses. Unlike conventional piezo-acoustic excitation of the cantilever, it allows for model-based quality (Q) factor control in order to increase the cantilever tracking bandwidth for tapping-mode AFM or to reduce resonant ringing for high-speed photothermal offresonance tapping (PORT) in ambient conditions. In this work, we present system identification, controller design and experimental results on controlling the Q factor of a photothermally driven cantilever. The work is expected to lay the groundwork for future implementations for high-speed PORT imaging in ambient conditions.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Photothermal excitation of the cantilever for dynamic atomic force microscopy (AFM) modes is an attractive actuation method as it provides clean cantilever actuation leading to well-defined frequency responses. Unlike conventional piezo-acoustic excitation of the cantilever, it allows for model-based quality (Q) factor control in order to increase the cantilever tracking bandwidth for tapping-mode AFM or to reduce resonant ringing for high-speed photothermal offresonance tapping (PORT) in ambient conditions. In this work, we present system identification, controller design and experimental results on controlling the Q factor of a photothermally driven cantilever. The work is expected to lay the groundwork for future implementations for high-speed PORT imaging in ambient conditions. |
| 191. |  | D. M. Harcombe; M. G. Ruppert; A. J. Fleming Modeling and Noise Analysis of a Microcantilever-based Mass Sensor Inproceedings Int. Conference on Manipulation, Automation and Robotics at Small Scales (MARSS), Helsinki, Finland, 2019. @inproceedings{Harcombe2019, title = {Modeling and Noise Analysis of a Microcantilever-based Mass Sensor}, author = {D. M. Harcombe and M. G. Ruppert and A. J. Fleming}, year = {2019}, date = {2019-07-01}, booktitle = {Int. Conference on Manipulation, Automation and Robotics at Small Scales (MARSS)}, address = {Helsinki, Finland}, abstract = {Nanomechanical devices have the potential for practical applications as mass sensors. In microcantilever based sensing, resonance frequency shifts are tracked by a phase-locked loop (PLL) in-order to monitor mass adsorption. A major challenge in minimizing the mass detection limit comes from the noise present in the system due to thermal, sensor and oscillator noise. There is numerical difficulty in simulating PLLs, as both low frequency phase estimates and high frequency mixing products need to be captured resulting in a stiff problem. By using linear system-theoretic modeling an in-depth analysis of the system is able to be conducted overcoming this issue. This provides insight into individual noise source propagation, dominant noise sources and possible ways to reduce their effects. The developed model is verified in simulation against the non-linear PLL, with each achieving low picogram sensitivity for a 100 Hz loop bandwidth and realistically modeled noise sources.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Nanomechanical devices have the potential for practical applications as mass sensors. In microcantilever based sensing, resonance frequency shifts are tracked by a phase-locked loop (PLL) in-order to monitor mass adsorption. A major challenge in minimizing the mass detection limit comes from the noise present in the system due to thermal, sensor and oscillator noise. There is numerical difficulty in simulating PLLs, as both low frequency phase estimates and high frequency mixing products need to be captured resulting in a stiff problem. By using linear system-theoretic modeling an in-depth analysis of the system is able to be conducted overcoming this issue. This provides insight into individual noise source propagation, dominant noise sources and possible ways to reduce their effects. The developed model is verified in simulation against the non-linear PLL, with each achieving low picogram sensitivity for a 100 Hz loop bandwidth and realistically modeled noise sources. |
| 190. |  | M. G. Ruppert; S. I. Moore; M. Zawierta; A. J. Fleming; G. Putrino; Y. K. Yong Multimodal atomic force microscopy with optimized higher eigenmode sensitivity using on-chip piezoelectric actuation and sensing Journal Article Nanotechnology, 30 (8), pp. 085503, 2019. @article{Ruppert2018b, title = {Multimodal atomic force microscopy with optimized higher eigenmode sensitivity using on-chip piezoelectric actuation and sensing}, author = {M. G. Ruppert and S. I. Moore and M. Zawierta and A. J. Fleming and G. Putrino and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2019/08/Ruppert_2019_Nanotechnology_30_085503.pdf}, doi = {https://doi.org/10.1088/1361-6528/aae40b}, year = {2019}, date = {2019-01-02}, journal = {Nanotechnology}, volume = {30}, number = {8}, pages = {085503}, abstract = {Atomic force microscope (AFM) cantilevers with integrated actuation and sensing provide several distinct advantages over conventional cantilever instrumentation. These include clean frequency responses, the possibility of down-scaling and parallelization to cantilever arrays as well as the absence of optical interference. While cantilever microfabrication technology has continuously advanced over the years, the overall design has remained largely unchanged; a passive rectangular shaped cantilever design has been adopted as the industry wide standard. In this article, we demonstrate multimode AFM imaging on higher eigenmodes as well as bimodal AFM imaging with cantilevers using fully integrated piezoelectric actuation and sensing. The cantilever design maximizes the higher eigenmode deflection sensitivity by optimizing the transducer layout according to the strain mode shape. Without the need for feedthrough cancellation, the read-out method achieves close to zero actuator/sensor feedthrough and the sensitivity is sufficient to resolve the cantilever Brownian motion.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Atomic force microscope (AFM) cantilevers with integrated actuation and sensing provide several distinct advantages over conventional cantilever instrumentation. These include clean frequency responses, the possibility of down-scaling and parallelization to cantilever arrays as well as the absence of optical interference. While cantilever microfabrication technology has continuously advanced over the years, the overall design has remained largely unchanged; a passive rectangular shaped cantilever design has been adopted as the industry wide standard. In this article, we demonstrate multimode AFM imaging on higher eigenmodes as well as bimodal AFM imaging with cantilevers using fully integrated piezoelectric actuation and sensing. The cantilever design maximizes the higher eigenmode deflection sensitivity by optimizing the transducer layout according to the strain mode shape. Without the need for feedthrough cancellation, the read-out method achieves close to zero actuator/sensor feedthrough and the sensitivity is sufficient to resolve the cantilever Brownian motion. |
2018 |
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| 189. |  | S. Z. Mansour; R. J. Seethaler; A. J. Fleming A Simple Asymmetric Hysteresis Model for Displacement-Force Control of Piezoelectric Actuators Inproceedings IEEE International Conference on Advanced Intelligent Mechatronics, Auckland, New Zealand, 2018. @inproceedings{C18f, title = {A Simple Asymmetric Hysteresis Model for Displacement-Force Control of Piezoelectric Actuators}, author = {S. Z. Mansour and R. J. Seethaler and A. J. Fleming}, year = {2018}, date = {2018-07-04}, booktitle = {IEEE International Conference on Advanced Intelligent Mechatronics}, address = {Auckland, New Zealand}, abstract = {This article presents a simple hysteresis model for piezoelectric actuators that can be used for simultaneous displacement-force control applications. The presented model maps the hysteresis voltage of an actuator to the charge passing through it. It can model asymmetric hysteresis loops and does not require to be inverted for real-time implementations. The presented model consists of two exponential functions which are described by only four parameters that are identified from a single identification experiment. Another advantage of the presented model over the existing models is that, it requires measurements of current rather than charge. A simultaneously varying displacement-force experiment is created to frame the model. An average absolute error value of 8% for the hysteresis voltage-charge fit is calculated. Consequent displacement and force fits have average absolute error value of 2.5%, which are similar to the best reported in displacement-force control literature.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This article presents a simple hysteresis model for piezoelectric actuators that can be used for simultaneous displacement-force control applications. The presented model maps the hysteresis voltage of an actuator to the charge passing through it. It can model asymmetric hysteresis loops and does not require to be inverted for real-time implementations. The presented model consists of two exponential functions which are described by only four parameters that are identified from a single identification experiment. Another advantage of the presented model over the existing models is that, it requires measurements of current rather than charge. A simultaneously varying displacement-force experiment is created to frame the model. An average absolute error value of 8% for the hysteresis voltage-charge fit is calculated. Consequent displacement and force fits have average absolute error value of 2.5%, which are similar to the best reported in displacement-force control literature. |
| 188. |  | M. Omidbeike; B. S. Routley; A. J. Fleming Independent Estimation of Temperature and Strain in Tee-Rosette Piezoresistive Strain Sensor Inproceedings IEEE International Conference on Advanced Intelligent Mechatronics, Auckland, New Zealand, 2018. @inproceedings{C18d, title = {Independent Estimation of Temperature and Strain in Tee-Rosette Piezoresistive Strain Sensor}, author = {M. Omidbeike and B. S. Routley and A. J. Fleming}, year = {2018}, date = {2018-07-04}, booktitle = {IEEE International Conference on Advanced Intelligent Mechatronics}, address = {Auckland, New Zealand}, abstract = {This article proposes a novel technique for independent measurement of strain and temperature in piezoresistive strain sensors configured in a tee-rosette. The most notable property of piezoresistive sensors is their easy integration into MEMS fabrication processes and nanopositioning systems which makes them highly advantageous for both size and cost. The foremost disadvantage associated with piezoresistive sensors is high temperature sensitivity. The proposed estimator allows independent estimation of strain and temperature, which eliminates drift due to temperature variation. Experimental results are presented for motion sensing of a piezoelectric stack actuator which shows a strain measurement with an accuracy of +/-6% over a temperature range of -15C to 40C.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This article proposes a novel technique for independent measurement of strain and temperature in piezoresistive strain sensors configured in a tee-rosette. The most notable property of piezoresistive sensors is their easy integration into MEMS fabrication processes and nanopositioning systems which makes them highly advantageous for both size and cost. The foremost disadvantage associated with piezoresistive sensors is high temperature sensitivity. The proposed estimator allows independent estimation of strain and temperature, which eliminates drift due to temperature variation. Experimental results are presented for motion sensing of a piezoelectric stack actuator which shows a strain measurement with an accuracy of +/-6% over a temperature range of -15C to 40C. |
| 187. |  | S. I. Moore; M. Omidbeike; A. J. Fleming; Y. K. Yong A monolithic serial-kinematic nanopositioner with integrated sensors and actuators Inproceedings IEEE International Conference on Advanced Intelligent Mechatronics, Auckland, New Zealand, 2018. @inproceedings{C18e, title = {A monolithic serial-kinematic nanopositioner with integrated sensors and actuators}, author = {S. I. Moore and M. Omidbeike and A. J. Fleming and Y. K. Yong}, year = {2018}, date = {2018-07-04}, booktitle = {IEEE International Conference on Advanced Intelligent Mechatronics}, address = {Auckland, New Zealand}, abstract = {This article describes the design, modeling and simulation of a serial-kinematic nanopositioner machined from a single sheet of piezoelectric material. In this class of nanopositioners, the flexures, sensors and actuators are completely integrated into a single monolithic structure. A non-trivial electrode topology is etched into the sheet to achieve in-plane bending and displacement of the moving platform. Finite element analysis predicts a sensitivity of 18.6 nm/V in the x-axis and 18.1 nm/V in the yaxis with a voltage limit of −250V to 1000 V. The first resonance frequency is 250 Hz in the Z axis. This design enables high-speed, long-range, lateral positioning in space-limited applications.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This article describes the design, modeling and simulation of a serial-kinematic nanopositioner machined from a single sheet of piezoelectric material. In this class of nanopositioners, the flexures, sensors and actuators are completely integrated into a single monolithic structure. A non-trivial electrode topology is etched into the sheet to achieve in-plane bending and displacement of the moving platform. Finite element analysis predicts a sensitivity of 18.6 nm/V in the x-axis and 18.1 nm/V in the yaxis with a voltage limit of −250V to 1000 V. The first resonance frequency is 250 Hz in the Z axis. This design enables high-speed, long-range, lateral positioning in space-limited applications. |
| 186. |  | Y. R. Teo; Y. K. Yong; A. J. Fleming A Comparison Of Scanning Methods And The Vertical Control Implications For Scanning Probe Microscopy Journal Article Asian Journal of Control, 30 (4), pp. 1-15, 2018. @article{J18f, title = {A Comparison Of Scanning Methods And The Vertical Control Implications For Scanning Probe Microscopy}, author = {Y. R. Teo and Y. K. Yong and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/01/J17d.pdf}, doi = {10.1002/asjc.1422}, year = {2018}, date = {2018-07-01}, journal = {Asian Journal of Control}, volume = {30}, number = {4}, pages = {1-15}, abstract = {This article compares the imaging performance of non-traditional scanning patterns for scanning probe microscopy including sinusoidal raster, spiral, and Lissajous patterns. The metrics under consideration include the probe velocity, scanning frequency, and required sampling rate. The probe velocity is investigated in detail as this quantity is proportional to the required bandwidth of the vertical feedback loop and has a major impact on image quality. By considering a sample with an impulsive Fourier transform, the effect of scanning trajectories on imaging quality can be observed and quantified. The non-linear trajectories are found to spread the topography signal bandwidth which has important implications for both low and high-speed imaging. These effects are studied analytically and demonstrated experimentally with a periodic calibration grating. }, keywords = {}, pubstate = {published}, tppubtype = {article} } This article compares the imaging performance of non-traditional scanning patterns for scanning probe microscopy including sinusoidal raster, spiral, and Lissajous patterns. The metrics under consideration include the probe velocity, scanning frequency, and required sampling rate. The probe velocity is investigated in detail as this quantity is proportional to the required bandwidth of the vertical feedback loop and has a major impact on image quality. By considering a sample with an impulsive Fourier transform, the effect of scanning trajectories on imaging quality can be observed and quantified. The non-linear trajectories are found to spread the topography signal bandwidth which has important implications for both low and high-speed imaging. These effects are studied analytically and demonstrated experimentally with a periodic calibration grating. |
| 185. |  | S. Z. Mansour; R. J. Seethaler; Y. R. Teo; Y. K. Yong; A. J. Fleming Piezoelectric Bimorph Actuator with Integrated Strain Sensing Electrodes Journal Article IEEE Sensors Journal, Prepress , 2018, ISSN: 1530-437X. @article{J18e, title = {Piezoelectric Bimorph Actuator with Integrated Strain Sensing Electrodes}, author = {S. Z. Mansour and R. J. Seethaler and Y. R. Teo and Y. K. Yong and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2018/06/J18e-Prepress.pdf}, doi = {10.1109/JSEN.2018.2842138}, issn = {1530-437X}, year = {2018}, date = {2018-07-01}, journal = {IEEE Sensors Journal}, volume = {Prepress}, abstract = {This article describes a new method for estimating the tip displacement of piezoelectric benders. Two resistive strain gauges are fabricated within the top and bottom electrodes using an acid etching process. These strain gauges are employed in a half bridge electrical configuration to measure the surface resistance change, and estimate the tip displacement. Experimental validation shows a 1.1 % maximum difference between the strain sensor and a laser triangulation sensor. Using the presented method, a damping-integral control structure is designed to control the tip displacement of the integrated bender}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article describes a new method for estimating the tip displacement of piezoelectric benders. Two resistive strain gauges are fabricated within the top and bottom electrodes using an acid etching process. These strain gauges are employed in a half bridge electrical configuration to measure the surface resistance change, and estimate the tip displacement. Experimental validation shows a 1.1 % maximum difference between the strain sensor and a laser triangulation sensor. Using the presented method, a damping-integral control structure is designed to control the tip displacement of the integrated bender |
| 184. |  | O. T. Ghalehbeygi; J. O'Connor; B. S. Routley; A. J. Fleming Iterative Deconvolution for Exposure Planning in Scanning Laser Lithography Inproceedings American Control Conference, Milwaukee, WI, 2018. @inproceedings{C18c, title = {Iterative Deconvolution for Exposure Planning in Scanning Laser Lithography}, author = {O. T. Ghalehbeygi and J. O'Connor and B. S. Routley and A. J. Fleming}, year = {2018}, date = {2018-06-27}, booktitle = {American Control Conference}, address = {Milwaukee, WI}, abstract = {Laser scanning lithography is a maskless method for exposing photoresist during semiconductor manufacturing. In this method, the power of a focused beam is modulated while scanning the photoresist. This article describes an iterative deconvolution method for determining the exposure pattern. This approach is computationally efficient as there is no gradient calculation. Simulations demonstrate the accurate fabrication of a feature with sub-wavelength geometry.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Laser scanning lithography is a maskless method for exposing photoresist during semiconductor manufacturing. In this method, the power of a focused beam is modulated while scanning the photoresist. This article describes an iterative deconvolution method for determining the exposure pattern. This approach is computationally efficient as there is no gradient calculation. Simulations demonstrate the accurate fabrication of a feature with sub-wavelength geometry. |
| 183. |  | M. G. Ruppert; D. M. Harcombe; S. I. Moore; A. J. Fleming Direct Design of Closed-loop Demodulators for Amplitude Modulation Atomic Force Microscopy Inproceedings American Control Conference, Milwaukee, WI, 2018. @inproceedings{C18b, title = {Direct Design of Closed-loop Demodulators for Amplitude Modulation Atomic Force Microscopy}, author = {M. G. Ruppert and D. M. Harcombe and S. I. Moore and A. J. Fleming}, year = {2018}, date = {2018-06-27}, booktitle = {American Control Conference}, address = {Milwaukee, WI}, abstract = {A fundamental component of the z-axis feedback loop in amplitude modulation atomic force microscopy is the demodulator. It dictates both bandwidth and noise in the amplitude and phase estimate of the cantilever deflection signal. In this paper, we derive a linear time-invariant model of a closedloop demodulator with user definable tracking bandwidth and sensitivity to other frequency components. A direct demodulator design method is proposed based on the reformulation of the Lyapunov filter as a modulated-demodulated controller in closed loop with a unity plant. Simulation and experimental results for a higher order Lyapunov filter as well as Butterworth and Chebyshev type demodulators are presented.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A fundamental component of the z-axis feedback loop in amplitude modulation atomic force microscopy is the demodulator. It dictates both bandwidth and noise in the amplitude and phase estimate of the cantilever deflection signal. In this paper, we derive a linear time-invariant model of a closedloop demodulator with user definable tracking bandwidth and sensitivity to other frequency components. A direct demodulator design method is proposed based on the reformulation of the Lyapunov filter as a modulated-demodulated controller in closed loop with a unity plant. Simulation and experimental results for a higher order Lyapunov filter as well as Butterworth and Chebyshev type demodulators are presented. |
| 182. |  | S. S. Aphale; M. Namavar; A. J. Fleming Resonance-shifting Integral Resonant Control for High-speed Nanopositioning Inproceedings American Control Conference, Milwaukee, WI, 2018. @inproceedings{C18a, title = {Resonance-shifting Integral Resonant Control for High-speed Nanopositioning}, author = {S. S. Aphale and M. Namavar and A. J. Fleming}, year = {2018}, date = {2018-06-27}, booktitle = {American Control Conference}, address = {Milwaukee, WI}, abstract = {The first resonance mode of mechanical systems is a significant limit to the achievable positioning bandwidth. This resonance is dependent on the physical, material and geometric properties of the system. Significant effort is typically required to increase the resonance frequency by increasing stiffness or reducing mass. In this article, a modified IRC scheme is presented that effectively shifts the first resonance mode to a higher frequency, thereby enabling a substantially higher positioning bandwidth. A 70% increase in positioning bandwidth is demonstrated.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } The first resonance mode of mechanical systems is a significant limit to the achievable positioning bandwidth. This resonance is dependent on the physical, material and geometric properties of the system. Significant effort is typically required to increase the resonance frequency by increasing stiffness or reducing mass. In this article, a modified IRC scheme is presented that effectively shifts the first resonance mode to a higher frequency, thereby enabling a substantially higher positioning bandwidth. A 70% increase in positioning bandwidth is demonstrated. |
| 181. |  | A. A. Eielsen; Y. R. Teo; A. J. Fleming Improving Robustness Filter Bandwidth in Repetitive Control by Considering Model Mismatch Journal Article Asian Journal of Control, 20 (3), pp. 1-11, 2018, ISSN: 1934-6093. @article{J18g, title = {Improving Robustness Filter Bandwidth in Repetitive Control by Considering Model Mismatch}, author = {A. A. Eielsen and Y. R. Teo and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/01/J17b.pdf}, doi = {10.1002/asjc.1437}, issn = {1934-6093}, year = {2018}, date = {2018-05-01}, journal = {Asian Journal of Control}, volume = {20}, number = {3}, pages = {1-11}, abstract = {Repetitive control (RC) is used to track and reject periodic signals by including a model of a periodic signal in the feedback path. The performance of RC can be improved by including an inverse plant response filter, but due to modeling uncertainty at high frequencies, a low-pass robustness filter is also required to limit the bandwidth of the signal model and ensure stability. The design of robustness filters is presently ad-hoc, which may result in excessively conservative performance. This article proposes a new automatic method for designing the robustness filter based on convex optimization and an uncertainty model. Experimental results on a nanopositioning system demonstrate that the proposed method outperforms the traditional brick-wall filter approach.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Repetitive control (RC) is used to track and reject periodic signals by including a model of a periodic signal in the feedback path. The performance of RC can be improved by including an inverse plant response filter, but due to modeling uncertainty at high frequencies, a low-pass robustness filter is also required to limit the bandwidth of the signal model and ensure stability. The design of robustness filters is presently ad-hoc, which may result in excessively conservative performance. This article proposes a new automatic method for designing the robustness filter based on convex optimization and an uncertainty model. Experimental results on a nanopositioning system demonstrate that the proposed method outperforms the traditional brick-wall filter approach. |
| 180. |  | D. M. Harcombe; M. G. Ruppert; M. R. P. Ragazzon; A. J. Fleming Lyapunov Estimation for High-Speed Demodulation in Multifrequency Atomic Force Microscopy Journal Article Beilstein Journal of Nanotechnology, 9 , pp. 490-498, 2018, ISSN: 21904286. @article{J18c, title = {Lyapunov Estimation for High-Speed Demodulation in Multifrequency Atomic Force Microscopy}, author = {D. M. Harcombe and M. G. Ruppert and M. R. P. Ragazzon and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2018/02/J18c.pdf}, doi = {10.3762/bjnano.9.47}, issn = {21904286}, year = {2018}, date = {2018-02-28}, journal = {Beilstein Journal of Nanotechnology}, volume = {9}, pages = {490-498}, abstract = {An important issue in the emerging field of multifrequency atomic force microscopy (MF-AFM) is the accurate and fast demodulation of the cantilever-tip deflection signal. As this signal consists of multiple frequency components and noise processes, a lock-in amplifier is typically employed for its narrowband response. However, this demodulator suffers inherent bandwidth limitations as high frequency mixing products must be filtered out and several must be operated in parallel. Many MF-AFM methods require amplitude and phase demodulation at multiple frequencies of interest, enabling both z-axis feedback and phase contrast imaging to be achieved. This article proposes a model-based multifrequency Lyapunov filter implemented on a Field Programmable Gate Array (FPGA) for high-speed MF-AFM demodulation. System descriptions and simulations are verified by experimental results demonstrating high tracking bandwidths, strong off-mode rejection and minor sensitivity to cross-coupling effects. Additionally, a five-frequency system operating at 3.5MHz is implemented for higher harmonic amplitude and phase imaging up to 1MHz.}, keywords = {}, pubstate = {published}, tppubtype = {article} } An important issue in the emerging field of multifrequency atomic force microscopy (MF-AFM) is the accurate and fast demodulation of the cantilever-tip deflection signal. As this signal consists of multiple frequency components and noise processes, a lock-in amplifier is typically employed for its narrowband response. However, this demodulator suffers inherent bandwidth limitations as high frequency mixing products must be filtered out and several must be operated in parallel. Many MF-AFM methods require amplitude and phase demodulation at multiple frequencies of interest, enabling both z-axis feedback and phase contrast imaging to be achieved. This article proposes a model-based multifrequency Lyapunov filter implemented on a Field Programmable Gate Array (FPGA) for high-speed MF-AFM demodulation. System descriptions and simulations are verified by experimental results demonstrating high tracking bandwidths, strong off-mode rejection and minor sensitivity to cross-coupling effects. Additionally, a five-frequency system operating at 3.5MHz is implemented for higher harmonic amplitude and phase imaging up to 1MHz. |
| 179. |  | S. A. Rios; A. J. Fleming; Y. K. Yong Monolithic Piezoelectric Insect with Resonance Walking Journal Article IEEE/ASME Transactions on Mechatronics, (In press) , 2018. @article{J18ab, title = {Monolithic Piezoelectric Insect with Resonance Walking}, author = {S. A. Rios and A. J. Fleming and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2018/01/J18a-PrePress.pdf}, year = {2018}, date = {2018-02-01}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {(In press)}, abstract = {This article describes the design, manufacture and performance of an untethered hexapod robot titled MinRAR V2. This robot utilizes a monolithic piezoelectric element, machined to allow for individual activation of bending actuators. The legs were designed so that the first two resonance modes overlap and therefore produce a walking motion at resonance. The monolithic construction significantly improves the matching of resonance modes between legs when compared to previous designs. Miniature control and high voltage driving electronics were designed to drive 24 separate piezoelectric elements powered from a single 3.7 V lithium polymer battery. The robot was driven both tethered and untethered and was able to achieve a maximum forward velocity of 98 mm/s when driven at 190 Hz and 6 mm/s at 5 Hz untethered. The robot is capable of a wide range of movements including banking, on the spot turning and reverse motion.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article describes the design, manufacture and performance of an untethered hexapod robot titled MinRAR V2. This robot utilizes a monolithic piezoelectric element, machined to allow for individual activation of bending actuators. The legs were designed so that the first two resonance modes overlap and therefore produce a walking motion at resonance. The monolithic construction significantly improves the matching of resonance modes between legs when compared to previous designs. Miniature control and high voltage driving electronics were designed to drive 24 separate piezoelectric elements powered from a single 3.7 V lithium polymer battery. The robot was driven both tethered and untethered and was able to achieve a maximum forward velocity of 98 mm/s when driven at 190 Hz and 6 mm/s at 5 Hz untethered. The robot is capable of a wide range of movements including banking, on the spot turning and reverse motion. |
| 178. |  | M. N. Islam; A. J. Fleming Resonance-enhanced Coupling for Range Extension of Electromagnetic Tracking Systems Journal Article IEEE Transactions on Magnetics, (In press) , 2018. @article{J18b, title = {Resonance-enhanced Coupling for Range Extension of Electromagnetic Tracking Systems}, author = {M. N. Islam and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/12/J18b.pdf}, year = {2018}, date = {2018-01-01}, journal = {IEEE Transactions on Magnetics}, volume = {(In press)}, abstract = {This article investigates the use of resonance-enhanced coupling to increase the received signal level in a six degree-of-freedom electromagnetic tracking system. Resonant coupling is found to increase the efficiency of the transmitter and increase the gain of the sensing coil, resulting in improved range. However, the measurement update rate is reduced due to the settling-time of the transmitter circuit and limited bandwidth of the sensing circuit. A resistive tuning approach is proposed to balance the trade-off between a decreased measurement bandwidth and improved signal level.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article investigates the use of resonance-enhanced coupling to increase the received signal level in a six degree-of-freedom electromagnetic tracking system. Resonant coupling is found to increase the efficiency of the transmitter and increase the gain of the sensing coil, resulting in improved range. However, the measurement update rate is reduced due to the settling-time of the transmitter circuit and limited bandwidth of the sensing circuit. A resistive tuning approach is proposed to balance the trade-off between a decreased measurement bandwidth and improved signal level. |
2017 |
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| 177. |  | A. J. Fleming; Y. K. Yong An Ultra-thin Monolithic XY Nanopositioning Stage Constructed from a Single Sheet of Piezoelectric Material Journal Article IEEE/ASME Transactions on Mechatronics, 22 (6), pp. 2611-2618, 2017, ISBN: 1083-4435. @article{J17k, title = {An Ultra-thin Monolithic XY Nanopositioning Stage Constructed from a Single Sheet of Piezoelectric Material}, author = {A. J. Fleming and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2018/01/J17k.pdf}, doi = {10.1109/TMECH.2017.2755659}, isbn = {1083-4435}, year = {2017}, date = {2017-12-20}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {22}, number = {6}, pages = {2611-2618}, abstract = {The article describes an XY nanopositioning stage constructed from flexures and actuators machined into a single sheet of piezoelectric material. Ultrasonic machining is used to remove piezoelectric material and create electrode features. The constructed device is 0.508mm thick and has a travel range of 8.8um in the X and Y axes. The first resonance mode occurs at 597Hz which makes the device suitable for a wide range of standard nanopositioning applications where cost and size are considerations. Experimental atomic force microscopy is performed using the proposed device as a sample scanner.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The article describes an XY nanopositioning stage constructed from flexures and actuators machined into a single sheet of piezoelectric material. Ultrasonic machining is used to remove piezoelectric material and create electrode features. The constructed device is 0.508mm thick and has a travel range of 8.8um in the X and Y axes. The first resonance mode occurs at 597Hz which makes the device suitable for a wide range of standard nanopositioning applications where cost and size are considerations. Experimental atomic force microscopy is performed using the proposed device as a sample scanner. |
| 176. |  | S. Z. Mansour; R. J. Seethaler; Y. R. Teo; Y. K. Yong; A. J. Fleming Piezoelectric Bimorph Actuator with Integrated Strain Sensing Electrodes Inproceedings IEEE Sensors, Glasgow, Scotland, 2017. @inproceedings{C17f, title = {Piezoelectric Bimorph Actuator with Integrated Strain Sensing Electrodes}, author = {S. Z. Mansour and R. J. Seethaler and Y. R. Teo and Y. K. Yong and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/08/Bender-paper.pdf}, year = {2017}, date = {2017-11-01}, booktitle = {IEEE Sensors}, address = {Glasgow, Scotland}, abstract = {This article describes a new method for estimating the tip displacement of piezoelectric benders. Two resistive strain gauges are fabricated within the top and bottom electrodes using an acid etching process. These strain gauges are employed in a half bridge electrical configuration to measure the surface resistance change, and estimate the tip displacement. Experimental validation shows a 1.1 % maximum difference between the strain sensor and a laser triangulation sensor.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This article describes a new method for estimating the tip displacement of piezoelectric benders. Two resistive strain gauges are fabricated within the top and bottom electrodes using an acid etching process. These strain gauges are employed in a half bridge electrical configuration to measure the surface resistance change, and estimate the tip displacement. Experimental validation shows a 1.1 % maximum difference between the strain sensor and a laser triangulation sensor. |
| 175. |  | A. A. Eielsen; A. J. Fleming Existing Methods for Improving the Accuracy of Digital-to-Analog Converters Journal Article Review of Scientific Instruments, 88 , pp. 094702, 2017. @article{J17i, title = {Existing Methods for Improving the Accuracy of Digital-to-Analog Converters}, author = {A. A. Eielsen and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/08/J17i.pdf}, doi = {10.1063/1.5000974}, year = {2017}, date = {2017-10-01}, journal = {Review of Scientific Instruments}, volume = {88}, pages = {094702}, abstract = {The performance of digital-to-analog converters is principally limited by errors in the output voltage levels. Such errors are known as element mismatch and are quantified by the integral non-linearity. Element mismatch limits the achievable accuracy and resolution in high-precision applications as it causes gain and offset error, as well as harmonic distortion. In this article, five existing methods for mitigating the effects of element mismatch are compared: physical level calibration, dynamic element matching, noise-shaping with digital calibration, large periodic high-frequency dithering, and large stochastic high-pass dithering. These methods are suitable for improving accuracy when using digital-to-analog converters that use multiple discrete output levels to reconstruct time-varying signals. The methods improve linearity and therefore reduce harmonic distortion, and can be retrofitted to existing systems with minor hardware variations. The performance of each method is compared theoretically and confirmed by simulations and experiments. Experimental results demonstrate that three of the five methods provide significant improvements in the resolution and accuracy when applied to a general-purpose digital-to-analog converter. As such, these methods can directly improve performance in a wide range of applications including nanopositioning, metrology, and optics.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The performance of digital-to-analog converters is principally limited by errors in the output voltage levels. Such errors are known as element mismatch and are quantified by the integral non-linearity. Element mismatch limits the achievable accuracy and resolution in high-precision applications as it causes gain and offset error, as well as harmonic distortion. In this article, five existing methods for mitigating the effects of element mismatch are compared: physical level calibration, dynamic element matching, noise-shaping with digital calibration, large periodic high-frequency dithering, and large stochastic high-pass dithering. These methods are suitable for improving accuracy when using digital-to-analog converters that use multiple discrete output levels to reconstruct time-varying signals. The methods improve linearity and therefore reduce harmonic distortion, and can be retrofitted to existing systems with minor hardware variations. The performance of each method is compared theoretically and confirmed by simulations and experiments. Experimental results demonstrate that three of the five methods provide significant improvements in the resolution and accuracy when applied to a general-purpose digital-to-analog converter. As such, these methods can directly improve performance in a wide range of applications including nanopositioning, metrology, and optics. |
| 174. |  | M. G. Ruppert; D. M. Harcombe; M. R. P. Ragazzon; S. O. R. Moheimani; A. J. Fleming A Review of Demodulation Techniques for Amplitude Modulation Atomic Force Microscopy Journal Article Bellstein Journal of Nanotechnology, 8 , pp. 1407–1426, 2017. @article{J17h, title = {A Review of Demodulation Techniques for Amplitude Modulation Atomic Force Microscopy}, author = {M. G. Ruppert and D. M. Harcombe and M. R. P. Ragazzon and S. O. R. Moheimani and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/08/2190-4286-8-142.pdf}, doi = {10.3762/bjnano.8.142}, year = {2017}, date = {2017-09-01}, journal = {Bellstein Journal of Nanotechnology}, volume = {8}, pages = {1407–1426}, abstract = {In this review paper, traditional and novel demodulation methods applicable to amplitude modulation atomic force microscopy are implemented on a widely used digital processing system. As a crucial bandwidth-limiting component in the z-axis feedback loop of an atomic force microscope, the purpose of the demodulator is to obtain estimates of amplitude and phase of the cantilever deflection signal in the presence of sensor noise or additional distinct frequency components. Specifically for modern multifrequency techniques, where higher harmonic and/or higher eigenmode contributions are present in the oscillation signal, the fidelity of the estimates obtained from some demodulation techniques is not guaranteed. To enable a rigorous comparison, the performance metrics tracking bandwidth, implementation complexity and sensitivity to other frequency components are experimentally evaluated for each method. Finally, the significance of an adequate demodulator bandwidth is highlighted during high-speed tapping-mode AFM experiments in constant height mode.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this review paper, traditional and novel demodulation methods applicable to amplitude modulation atomic force microscopy are implemented on a widely used digital processing system. As a crucial bandwidth-limiting component in the z-axis feedback loop of an atomic force microscope, the purpose of the demodulator is to obtain estimates of amplitude and phase of the cantilever deflection signal in the presence of sensor noise or additional distinct frequency components. Specifically for modern multifrequency techniques, where higher harmonic and/or higher eigenmode contributions are present in the oscillation signal, the fidelity of the estimates obtained from some demodulation techniques is not guaranteed. To enable a rigorous comparison, the performance metrics tracking bandwidth, implementation complexity and sensitivity to other frequency components are experimentally evaluated for each method. Finally, the significance of an adequate demodulator bandwidth is highlighted during high-speed tapping-mode AFM experiments in constant height mode. |
| 173. |  | O. T. Ghalehbeygi; A. G. Wills; B. S. Routley; A. J. Fleming Gradient-based optimization for efficient exposure planning in maskless lithography Journal Article Journal of Micro/Nanolithography, MEMS, and MOEMS, 16 (3), pp. 033507, 2017. @article{J17j, title = {Gradient-based optimization for efficient exposure planning in maskless lithography}, author = {O. T. Ghalehbeygi and A. G. Wills and B. S. Routley and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/09/J17j.pdf}, doi = {10.1117/1.JMM.16.3.033507}, year = {2017}, date = {2017-09-01}, journal = {Journal of Micro/Nanolithography, MEMS, and MOEMS}, volume = {16}, number = {3}, pages = {033507}, abstract = {Scanning laser lithography is a maskless method for exposing photoresist during semiconductor manufacturing. In this method, the energy of a focused beam is controlled while scanning the beam or substrate. With a positive photoresist material, areas that receive an exposure dosage over the threshold energy are dissolved during development. The surface dosage is related to the exposure profile by a convolution and nonlinear function, so the optimal exposure profile is nontrivial. A gradient-based optimization method for determining an optimal exposure profile, given the desired pattern and models of the beam profile and photochemistry, is described. This approach is more numerically efficient than optimal barrier-function-based methods but provides near-identical results. This is demonstrated through simulation and experimental lithography}, keywords = {}, pubstate = {published}, tppubtype = {article} } Scanning laser lithography is a maskless method for exposing photoresist during semiconductor manufacturing. In this method, the energy of a focused beam is controlled while scanning the beam or substrate. With a positive photoresist material, areas that receive an exposure dosage over the threshold energy are dissolved during development. The surface dosage is related to the exposure profile by a convolution and nonlinear function, so the optimal exposure profile is nontrivial. A gradient-based optimization method for determining an optimal exposure profile, given the desired pattern and models of the beam profile and photochemistry, is described. This approach is more numerically efficient than optimal barrier-function-based methods but provides near-identical results. This is demonstrated through simulation and experimental lithography |
| 172. |  | M. N. Islam; A. J. Fleming An Algorithm for Transmitter Optimization in Electromagnetic Tracking Systems Journal Article IEEE Transactions on Magnetics, 53 (8), pp. 1-8, 2017, ISBN: 0018-9464. @article{J17g, title = {An Algorithm for Transmitter Optimization in Electromagnetic Tracking Systems}, author = {M. N. Islam and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/05/07926412.pdf}, doi = {10.1109/TMAG.2017.2703653}, isbn = {0018-9464}, year = {2017}, date = {2017-08-30}, journal = {IEEE Transactions on Magnetics}, volume = {53}, number = {8}, pages = {1-8}, abstract = {Electromagnetic tracking systems are used extensively in biomedical devices, gaming consoles, and animation because they are inexpensive and do not require line of sight. However, the measurement range is limited by the amplitude of the induced voltage in the sensing coil. The induced voltage is a function of the transmitter parameters such as the coil dimensions, signal power, and frequency. The transmitted power is typically restricted by the physical constraints in the application. This paper develops an algorithm to optimize the dimensions of the transmitting coil for maximum induced voltage. The proposed method is suitable for a transmitter consisting of three concentric orthogonal transmitting coils of the type commonly used in six-degree-of-freedom localization. The simulation and experimental results are presented, which demonstrate the efficacy of the proposed method.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Electromagnetic tracking systems are used extensively in biomedical devices, gaming consoles, and animation because they are inexpensive and do not require line of sight. However, the measurement range is limited by the amplitude of the induced voltage in the sensing coil. The induced voltage is a function of the transmitter parameters such as the coil dimensions, signal power, and frequency. The transmitted power is typically restricted by the physical constraints in the application. This paper develops an algorithm to optimize the dimensions of the transmitting coil for maximum induced voltage. The proposed method is suitable for a transmitter consisting of three concentric orthogonal transmitting coils of the type commonly used in six-degree-of-freedom localization. The simulation and experimental results are presented, which demonstrate the efficacy of the proposed method. |
| 171. |  | Y. K. Yong; A. J. Fleming An Improved Low-frequency Correction Technique for Piezoelectric Force Sensors in High-speed Nanopositioning Systems Journal Article Review of Scientific Instruments, 88 (046105), pp. 1-3, 2017. @article{J17f, title = {An Improved Low-frequency Correction Technique for Piezoelectric Force Sensors in High-speed Nanopositioning Systems}, author = {Y. K. Yong and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/08/Yong2017_note.pdf}, year = {2017}, date = {2017-08-02}, journal = {Review of Scientific Instruments}, volume = {88}, number = {046105}, pages = {1-3}, abstract = {Piezoelectric force and position sensors provide high sensitivity but are limited at low frequencies due to their high-pass response which complicates the direct application of integral control. To overcome this issue, an additional sensor or low-frequency correction method is typically employed. However, these approaches introduce an additional first-order response that must be higher than the high-pass response of the piezo and interface electronics. This article describes a simplified method for low-frequency correction that uses the piezoelectric sensor as an electrical component in a filter circuit. The resulting response is first-order, rather than second-order, with a cut-off frequency equal to that of a buffer circuit with the same input resistance. The proposed method is demonstrated to allow simultaneous damping and tracking control of a high-speed vertical nanopositioning stage}, keywords = {}, pubstate = {published}, tppubtype = {article} } Piezoelectric force and position sensors provide high sensitivity but are limited at low frequencies due to their high-pass response which complicates the direct application of integral control. To overcome this issue, an additional sensor or low-frequency correction method is typically employed. However, these approaches introduce an additional first-order response that must be higher than the high-pass response of the piezo and interface electronics. This article describes a simplified method for low-frequency correction that uses the piezoelectric sensor as an electrical component in a filter circuit. The resulting response is first-order, rather than second-order, with a cut-off frequency equal to that of a buffer circuit with the same input resistance. The proposed method is demonstrated to allow simultaneous damping and tracking control of a high-speed vertical nanopositioning stage |
| 170. |  | M. R. P. Ragazzon; M. G. Ruppert; D. M. Harcombe; A. J. Fleming; J. T. Gravdahl Lyapunov Estimator for High-Speed Demodulation in Dynamic Mode Atomic Force Microscopy Journal Article IEEE Transactions on Control Systems Technology, 26 (2), pp. 765-772, 2017. @article{J17e, title = {Lyapunov Estimator for High-Speed Demodulation in Dynamic Mode Atomic Force Microscopy}, author = {M. R. P. Ragazzon and M. G. Ruppert and D. M. Harcombe and A. J. Fleming and J. T. Gravdahl}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/09/J17e.pdf}, year = {2017}, date = {2017-08-01}, journal = {IEEE Transactions on Control Systems Technology}, volume = {26}, number = {2}, pages = {765-772}, abstract = {In dynamic mode atomic force microscopy (AFM), the imaging bandwidth is governed by the slowest component in the open-loop chain consisting of the vertical actuator, cantilever and demodulator. While the common demodulation method is to use a lock-in amplifier (LIA), its performance is ultimately bounded by the bandwidth of the post-mixing low-pass filters. This article proposes an amplitude and phase estimation method based on a strictly positive real Lyapunov design approach. The estimator is designed to be of low complexity while allowing for high bandwidth. Additionally, suitable gains for high performance are suggested such that no tuning is necessary. The Lyapunov estimator is experimentally implemented for amplitude demodulation and shown to surpass the LIA in terms of tracking bandwidth and noise performance. High-speed AFM images are presented to corroborate the results.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In dynamic mode atomic force microscopy (AFM), the imaging bandwidth is governed by the slowest component in the open-loop chain consisting of the vertical actuator, cantilever and demodulator. While the common demodulation method is to use a lock-in amplifier (LIA), its performance is ultimately bounded by the bandwidth of the post-mixing low-pass filters. This article proposes an amplitude and phase estimation method based on a strictly positive real Lyapunov design approach. The estimator is designed to be of low complexity while allowing for high bandwidth. Additionally, suitable gains for high performance are suggested such that no tuning is necessary. The Lyapunov estimator is experimentally implemented for amplitude demodulation and shown to surpass the LIA in terms of tracking bandwidth and noise performance. High-speed AFM images are presented to corroborate the results. |
| 169. |  | M. Omidbeike; Y. R. Teo; Y. K. Yong; A. J. Fleming Tracking Control of a Monolithic Piezoelectric Nanopositioning Stage using an Integrated Sensor Inproceedings IFAC World Congress, Toulouse, France, 2017. @inproceedings{C17d, title = {Tracking Control of a Monolithic Piezoelectric Nanopositioning Stage using an Integrated Sensor}, author = {M. Omidbeike and Y. R. Teo and Y. K. Yong and A. J. Fleming}, year = {2017}, date = {2017-07-09}, booktitle = {IFAC World Congress}, address = {Toulouse, France}, abstract = {This article describes a method for tracking control of monolithic nanopositioning systems using integrated piezoelectric sensors. The monolithic nanopositioner is constructed from a single sheet of piezoelectric material where a set of flexures are used for actuation and guidance, and another set are used for position sensing. This arrangement is shown to be highly sensitive to in-plane motion (in the x- and y-axis) and insensitive to vertical motion, which is ideal for position tracking control. The foremost difficulty with piezoelectric sensors is their low-frequency high-pass response. In this article, a simple estimator circuit is used to allow the direct application of integral tracking control. Although the system operates in open-loop at DC, dynamic command signals such as scanning trajectories are accurately tracked. Experimental results show significant improvements in linearity and positioning error. }, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This article describes a method for tracking control of monolithic nanopositioning systems using integrated piezoelectric sensors. The monolithic nanopositioner is constructed from a single sheet of piezoelectric material where a set of flexures are used for actuation and guidance, and another set are used for position sensing. This arrangement is shown to be highly sensitive to in-plane motion (in the x- and y-axis) and insensitive to vertical motion, which is ideal for position tracking control. The foremost difficulty with piezoelectric sensors is their low-frequency high-pass response. In this article, a simple estimator circuit is used to allow the direct application of integral tracking control. Although the system operates in open-loop at DC, dynamic command signals such as scanning trajectories are accurately tracked. Experimental results show significant improvements in linearity and positioning error. |
| 168. |  | D. M. Harcombe; M. G. Ruppert; A. J. Fleming Higher-harmonic AFM Imaging with a High-Bandwidth Multifrequency Lyapunov Filter Inproceedings IEEE/ASME Advanced Intelligent Mechatronics (AIM), Munich, Germany, 2017. @inproceedings{C17e, title = {Higher-harmonic AFM Imaging with a High-Bandwidth Multifrequency Lyapunov Filter}, author = {D. M. Harcombe and M. G. Ruppert and A. J. Fleming}, year = {2017}, date = {2017-07-03}, booktitle = {IEEE/ASME Advanced Intelligent Mechatronics (AIM)}, address = {Munich, Germany}, abstract = {A major difficulty in multifrequency atomic force microscopy (MF-AFM) is the accurate estimation of amplitude and phase at multiple frequencies for both z-axis feedback and material contrast imaging. Typically a lock-in amplifier is chosen as it is both narrowband and simple to implement. However, it inherently suffers drawbacks including a limited bandwidth due to post mixing low-pass filters and the necessity for multiple to be operated in parallel for MF-AFM. This paper proposes a multifrequency demodulator in the form of a modelbased Lyapunov filter implemented on a Field Programmable Gate Array (FPGA). System modelling and simulations are verified by experimental results demonstrating high tracking bandwidth and off-mode rejection at modelled frequencies. Additionally, AFM scans with a five-frequency-based system are presented wherein higher harmonic imaging is performed up to 1 MHz.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A major difficulty in multifrequency atomic force microscopy (MF-AFM) is the accurate estimation of amplitude and phase at multiple frequencies for both z-axis feedback and material contrast imaging. Typically a lock-in amplifier is chosen as it is both narrowband and simple to implement. However, it inherently suffers drawbacks including a limited bandwidth due to post mixing low-pass filters and the necessity for multiple to be operated in parallel for MF-AFM. This paper proposes a multifrequency demodulator in the form of a modelbased Lyapunov filter implemented on a Field Programmable Gate Array (FPGA). System modelling and simulations are verified by experimental results demonstrating high tracking bandwidth and off-mode rejection at modelled frequencies. Additionally, AFM scans with a five-frequency-based system are presented wherein higher harmonic imaging is performed up to 1 MHz. |
| 167. |  | A. A. Eielsen; A. J. Fleming Improving Digital-to-analog Converter Linearity by Large High-frequency Dithering Journal Article IEEE Transactions on Circuits and Systems I, 64 (6), pp. 1409-1420, 2017, ISSN: 1549-8328. @article{J17c, title = {Improving Digital-to-analog Converter Linearity by Large High-frequency Dithering}, author = {A. A. Eielsen and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2020/06/J17c.pdf}, doi = {10.1109/TCSI.2016.2561778}, issn = {1549-8328}, year = {2017}, date = {2017-07-01}, journal = {IEEE Transactions on Circuits and Systems I}, volume = {64}, number = {6}, pages = {1409-1420}, abstract = {A new method for reducing harmonic distortion due to element mismatch in digital-to-analog converters is described. This is achieved by using a large high-frequency periodic dither. The reduction in non-linearity is due to the smoothing effect this dither has on the non-linearity, which is only dependent on the amplitude distribution function of the dither. Since the high-frequency dither is unwanted on the output on the digital-to-analog converter, the dither is removed by an output filter. The fundamental frequency component of the dither is attenuated by a passive notch filter and the remaining fundamental component and harmonic components are attenuated by the low-pass reconstruction filter. Two methods that further improve performance are also presented. By reproducing the dither on a second channel and subtracting it using a differential amplifier, additional dither attenuation is achieved; and by averaging several channels, the noise-floor of the output is improved. Experimental results demonstrate more than 10 dB improvement in the signal-to-noise-and-distortion ratio.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new method for reducing harmonic distortion due to element mismatch in digital-to-analog converters is described. This is achieved by using a large high-frequency periodic dither. The reduction in non-linearity is due to the smoothing effect this dither has on the non-linearity, which is only dependent on the amplitude distribution function of the dither. Since the high-frequency dither is unwanted on the output on the digital-to-analog converter, the dither is removed by an output filter. The fundamental frequency component of the dither is attenuated by a passive notch filter and the remaining fundamental component and harmonic components are attenuated by the low-pass reconstruction filter. Two methods that further improve performance are also presented. By reproducing the dither on a second channel and subtracting it using a differential amplifier, additional dither attenuation is achieved; and by averaging several channels, the noise-floor of the output is improved. Experimental results demonstrate more than 10 dB improvement in the signal-to-noise-and-distortion ratio. |
| 166. |  | B. S. Routley; F. Miteff; A. J. Fleming Modelling and Control of Nitrogen Partial Pressure for Prophylaxis and Treatment of Air Embolism Inproceedings American Control Conference, Seattle, WA, 2017. @inproceedings{C17a, title = {Modelling and Control of Nitrogen Partial Pressure for Prophylaxis and Treatment of Air Embolism}, author = {B. S. Routley and F. Miteff and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/03/modelling-control-nitrogen-10.pdf}, year = {2017}, date = {2017-05-01}, booktitle = {American Control Conference}, address = {Seattle, WA}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 165. |  | M. G. Ruppert; D. M. Harcombe; M. R. P. Ragazzon; S. O. R. Moheimani; A. J. Fleming Frequency Domain Analysis of Robust Demodulators for High-Speed Atomic Force Microscopy Inproceedings American Control Conference, Seattle, WA, 2017. @inproceedings{C17b, title = {Frequency Domain Analysis of Robust Demodulators for High-Speed Atomic Force Microscopy}, author = {M. G. Ruppert and D. M. Harcombe and M. R. P. Ragazzon and S. O. R. Moheimani and A. J. Fleming}, year = {2017}, date = {2017-05-01}, booktitle = {American Control Conference}, address = {Seattle, WA}, abstract = {A fundamental but often overlooked component in the z-axis feedback loop of the atomic force microscope (AFM) operated in dynamic mode is the demodulator. It’s purpose is to obtain a preferably fast and low-noise estimate of amplitude and phase of the cantilever deflection signal in the presence of sensor noise and additional distinct frequency components. In this paper, we implement both traditional and recently developed robust methods on a labVIEW digital processing system and rigorously compare these techniques experimentally in terms of measurement bandwidth, implementation complexity and robustness to noise. We conclude with showing high-speed tapping-mode AFM images in constant height, highlighting the significance of an adequate demodulator bandwidth.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A fundamental but often overlooked component in the z-axis feedback loop of the atomic force microscope (AFM) operated in dynamic mode is the demodulator. It’s purpose is to obtain a preferably fast and low-noise estimate of amplitude and phase of the cantilever deflection signal in the presence of sensor noise and additional distinct frequency components. In this paper, we implement both traditional and recently developed robust methods on a labVIEW digital processing system and rigorously compare these techniques experimentally in terms of measurement bandwidth, implementation complexity and robustness to noise. We conclude with showing high-speed tapping-mode AFM images in constant height, highlighting the significance of an adequate demodulator bandwidth. |
| 164. |  | S. A. Rios; A. J. Fleming; Y. K. Yong Miniature Resonant Ambulatory Robot Journal Article IEEE Robotics and Automation Letters, 2 (1), pp. 337–343, 2017, ISSN: 2377-3766. @article{J17a, title = {Miniature Resonant Ambulatory Robot}, author = {S. A. Rios and A. J. Fleming and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/01/J17a.pdf}, doi = {10.1109/LRA.2016.2614837}, issn = {2377-3766}, year = {2017}, date = {2017-01-01}, journal = {IEEE Robotics and Automation Letters}, volume = {2}, number = {1}, pages = {337--343}, abstract = {This article describes the design, manufacture, and performance of a prototype miniature resonant ambulatory robot that uses piezoelectric actuators to achieve locomotion. Each leg is comprised of two piezoelectric bimorph benders, joined at the tip by a flexure and end effector. Combinations of amplitude and phase can be used to produce a wide range of motions including swinging and lifting. A lumped mass model previously developed is described as a design tool to tune the resonance modes of the end effector. The completed robot was driven with frequencies up to 500 Hz resulting in a maximum forward velocity of approximately 520 mm/s at 350 Hz. A frequency analysis was also performed to determine the effects of ground contact on the performance of the robot. This analysis showed a significant reduction in the resonance gain and frequency.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article describes the design, manufacture, and performance of a prototype miniature resonant ambulatory robot that uses piezoelectric actuators to achieve locomotion. Each leg is comprised of two piezoelectric bimorph benders, joined at the tip by a flexure and end effector. Combinations of amplitude and phase can be used to produce a wide range of motions including swinging and lifting. A lumped mass model previously developed is described as a design tool to tune the resonance modes of the end effector. The completed robot was driven with frequencies up to 500 Hz resulting in a maximum forward velocity of approximately 520 mm/s at 350 Hz. A frequency analysis was also performed to determine the effects of ground contact on the performance of the robot. This analysis showed a significant reduction in the resonance gain and frequency. |
2016 |
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| 163. |  | A. A. Eielsen; A. J. Fleming Improving DAC Resolution in Closed-Loop Control of Precision Mechatronic Systems Using Dithering Inproceedings IEEE Conference on Decision and Control, Las Vegas, NV, 2016. @inproceedings{C16k, title = {Improving DAC Resolution in Closed-Loop Control of Precision Mechatronic Systems Using Dithering}, author = {A. A. Eielsen and A. J. Fleming}, year = {2016}, date = {2016-12-12}, booktitle = {IEEE Conference on Decision and Control}, address = {Las Vegas, NV}, abstract = {The resolution of precision mechatronic systems is fundamentally limited by the the noise and distortion performance of digital-to-analog converters. The sources of noise and distortion include quantization error, non-linearity, thermal noise, and semiconductor noise. In precision control applications, the primary limitation is harmonic distortion due to quantization and element mismatch. In this article, quantization noise and harmonic distortion are reduced by combinations of small noise dithers and large high-frequency periodic dithers. Theoretical predictions are confirmed experimentally on a closed-loop nanopositioning system. The results show reasonable correspondence to simulation and a significant reduction in noise due to quantization and element mismatch.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } The resolution of precision mechatronic systems is fundamentally limited by the the noise and distortion performance of digital-to-analog converters. The sources of noise and distortion include quantization error, non-linearity, thermal noise, and semiconductor noise. In precision control applications, the primary limitation is harmonic distortion due to quantization and element mismatch. In this article, quantization noise and harmonic distortion are reduced by combinations of small noise dithers and large high-frequency periodic dithers. Theoretical predictions are confirmed experimentally on a closed-loop nanopositioning system. The results show reasonable correspondence to simulation and a significant reduction in noise due to quantization and element mismatch. |
| 162. |  | A. J. Fleming; A. G. Wills; B. S. Routley Exposure Optimization in Scanning Laser Lithography Journal Article IEEE Potentials, 35 (4), pp. 33-39, 2016, ISSN: 0278-6648. @article{J16b, title = {Exposure Optimization in Scanning Laser Lithography}, author = {A. J. Fleming and A. G. Wills and B. S. Routley}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2016/08/J16b.pdf}, doi = {10.1109/MPOT.2016.2540039}, issn = {0278-6648}, year = {2016}, date = {2016-12-01}, journal = {IEEE Potentials}, volume = {35}, number = {4}, pages = {33-39}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 161. |  | Y. K. Yong; A. J. Fleming High-speed Vertical Positioning Stage with Integrated Dual-sensor Arrangement Journal Article Sensors & Actuators: A. Physical, 248 , pp. 184–192, 2016. @article{J16d, title = {High-speed Vertical Positioning Stage with Integrated Dual-sensor Arrangement}, author = {Y. K. Yong and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2016/08/1-s2.0-S0924424716303302-main-1.pdf}, year = {2016}, date = {2016-12-01}, journal = {Sensors & Actuators: A. Physical}, volume = {248}, pages = {184--192}, abstract = {This article presents a novel vertical positioning stage with a dual-sensor arrangement suitable for scanning probe microscopy. The stage has a travel range of 8.4um and a first resonance frequency of 24kHz in the direction of travel. The sensor arrangement consists of an integrated piezoelectric force sensor and laminated piezoresistive strain sensor. The piezoelectric force sensor exhibits extremely low noise and introduces a zero into the dynamics which allows the use of integral force feedback. This control method provides excellent damping performance and guaranteed stability. The piezoresistive sensor is used for tracking control with an analog PI controller which is shown to be an approximate inverse of the damped system. The resulting closed-loop system has a bandwidth is 11.4kHz and 6-sigma resolution of 3.6nm, which is ideal for nanopositioning and atomic force microscopy (AFM) applications. The proposed vertical stage is used to replace the vertical axis of a commercial AFM. Scans are performed in constant-force contact mode with a tip velocity of 0.2mm/s, 1mm/s and 2mm/s. The recorded images contain negligible artefacts due to insufficient vertical bandwidth.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article presents a novel vertical positioning stage with a dual-sensor arrangement suitable for scanning probe microscopy. The stage has a travel range of 8.4um and a first resonance frequency of 24kHz in the direction of travel. The sensor arrangement consists of an integrated piezoelectric force sensor and laminated piezoresistive strain sensor. The piezoelectric force sensor exhibits extremely low noise and introduces a zero into the dynamics which allows the use of integral force feedback. This control method provides excellent damping performance and guaranteed stability. The piezoresistive sensor is used for tracking control with an analog PI controller which is shown to be an approximate inverse of the damped system. The resulting closed-loop system has a bandwidth is 11.4kHz and 6-sigma resolution of 3.6nm, which is ideal for nanopositioning and atomic force microscopy (AFM) applications. The proposed vertical stage is used to replace the vertical axis of a commercial AFM. Scans are performed in constant-force contact mode with a tip velocity of 0.2mm/s, 1mm/s and 2mm/s. The recorded images contain negligible artefacts due to insufficient vertical bandwidth. |
| 160. |  | A. A. Eielsen; A. J. Fleming Experimental Assessment of Dynamic Digital-to-Analog Converter Performance for Applications in Precision Mechatronic Systems Inproceedings Australian Control Conference, Newcastle, Australia, 2016. @inproceedings{C16f, title = {Experimental Assessment of Dynamic Digital-to-Analog Converter Performance for Applications in Precision Mechatronic Systems}, author = {A. A. Eielsen and A. J. Fleming}, year = {2016}, date = {2016-11-05}, booktitle = {Australian Control Conference}, address = {Newcastle, Australia}, abstract = {An experimental assessment of some state-of-the-art commercially available digital-to-analog converters (DACs) is presented. A DAC is the principal enabling device for implementing modern digital feed-forward and feedback control. For precision mechatronic systems employing the best available instrumentation, the main limitation to resolution is presently the noise and distortion performance of DACs. The paper focuses on measuring the dynamic performance of the DACs, that is, the maximum resolution that can be achieved in practice when using the DACs for trajectory tracking, as well as the time-delay introduced due to DAC latency.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } An experimental assessment of some state-of-the-art commercially available digital-to-analog converters (DACs) is presented. A DAC is the principal enabling device for implementing modern digital feed-forward and feedback control. For precision mechatronic systems employing the best available instrumentation, the main limitation to resolution is presently the noise and distortion performance of DACs. The paper focuses on measuring the dynamic performance of the DACs, that is, the maximum resolution that can be achieved in practice when using the DACs for trajectory tracking, as well as the time-delay introduced due to DAC latency. |
| 159. |  | R. de Rozario; A. J. Fleming; T. Oomen Iterative Control for Periodic Tasks with Robustness Considerations, Applied to a Nanopositioning Stage Inproceedings IFAC Symposium on Mechatronic Systems, Loughborough, UK, 2016. @inproceedings{C16g, title = {Iterative Control for Periodic Tasks with Robustness Considerations, Applied to a Nanopositioning Stage}, author = {R. de Rozario and A. J. Fleming and T. Oomen}, year = {2016}, date = {2016-09-05}, booktitle = {IFAC Symposium on Mechatronic Systems}, address = {Loughborough, UK}, abstract = {Nanopositioning stages are an example of motion systems that are required to accurately perform a high frequent repetitive scanning motion. The tracking performance can be signi cantly increased by iteratively updating a feedforward input by using a nonparametric inverse plant model. However, in this paper it is shown that current approaches lack systematic robustness considerations and are su ering from limited design freedom to enforce satisfying convergence behavior. Therefore, inspired by existing the Iterative Learning Control approach, robustness is added to the existing methods to enable the desired convergence behavior. This results in the Robust Iterative Inversion-based Control method, whose potential for superior convergence is experimentally veri ed on a Nanopositioning system.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Nanopositioning stages are an example of motion systems that are required to accurately perform a high frequent repetitive scanning motion. The tracking performance can be signi cantly increased by iteratively updating a feedforward input by using a nonparametric inverse plant model. However, in this paper it is shown that current approaches lack systematic robustness considerations and are su ering from limited design freedom to enforce satisfying convergence behavior. Therefore, inspired by existing the Iterative Learning Control approach, robustness is added to the existing methods to enable the desired convergence behavior. This results in the Robust Iterative Inversion-based Control method, whose potential for superior convergence is experimentally veri ed on a Nanopositioning system. |
| 158. |  | Y. K. Yong; S. P. Wadikhaye; A. J. Fleming High-Speed Single-Stage and Dual-Stage Vertical Positioners Journal Article Review of Scientific Instruments, 87 (085104), pp. (1-8), 2016. @article{J16e, title = {High-Speed Single-Stage and Dual-Stage Vertical Positioners}, author = {Y. K. Yong and S. P. Wadikhaye and A. J. Fleming }, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/01/J16e.pdf}, year = {2016}, date = {2016-09-01}, journal = {Review of Scientific Instruments}, volume = {87}, number = {085104}, pages = {(1-8)}, abstract = {This article presents a high-speed single- and dual-stage vertical positioner for applications in optical systems. Each positioner employs a unique end-constraint method with orthogonal flexures to preload a piezoelectric stack actuator. This end-constraint method also significantly increases the first mechanical resonance frequency. The single-stage positioner has a displacement range of 7.6um and a first resonance frequency of 46.8kHz. The dual-stage design consists of a long-range slow-stage and a short-range fast-stage. An inertial counterbalance technique was implemented on the fast-stage to cancel inertial forces resulting from high-speed motion. The dual-stage positioner has a combined travel range of approximately 10um and a first evident resonance frequency of 130kHz.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article presents a high-speed single- and dual-stage vertical positioner for applications in optical systems. Each positioner employs a unique end-constraint method with orthogonal flexures to preload a piezoelectric stack actuator. This end-constraint method also significantly increases the first mechanical resonance frequency. The single-stage positioner has a displacement range of 7.6um and a first resonance frequency of 46.8kHz. The dual-stage design consists of a long-range slow-stage and a short-range fast-stage. An inertial counterbalance technique was implemented on the fast-stage to cancel inertial forces resulting from high-speed motion. The dual-stage positioner has a combined travel range of approximately 10um and a first evident resonance frequency of 130kHz. |
| 157. |  | Y. R. Teo; A. A. Eielsen; J. T. Gravdahl; A. J. Fleming A Simplified Method For Discrete-Time Repetitive Control Using Model-Less FIR Filter Inversion Journal Article Journal of Dynamic Systems, Measurement and Control, 138 (8), pp. 081002, 2016. @article{J16c, title = {A Simplified Method For Discrete-Time Repetitive Control Using Model-Less FIR Filter Inversion}, author = {Y. R. Teo and A. A. Eielsen and J. T. Gravdahl and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2016/06/J16c.pdf}, doi = {10.1115/1.4033274}, year = {2016}, date = {2016-08-01}, journal = {Journal of Dynamic Systems, Measurement and Control}, volume = {138}, number = {8}, pages = {081002}, abstract = {Repetitive control (RC) achieves tracking and rejection of periodic exogenous signals by incorporating a model of a periodic signal in the feedback path. To improve the performance, an inverse plant response filter (IPRF) is used. To improve robustness, the periodic signal model is bandwidth-limited. This limitation is largely dependent on the accuracy of the IPRF. A new method is presented for synthesizing the IPRF for discrete-time RC. The method produces filters in a simpler and more consistent manner than existing best-practice methods available in the literature, as the only variable involved is the selection of a windowing function. It is also more efficient in terms of memory and computational complexity than existing methods. Experimental results for a nanopositioning stage show that the proposed method yields the same or better tracking performance compared to existing methods.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Repetitive control (RC) achieves tracking and rejection of periodic exogenous signals by incorporating a model of a periodic signal in the feedback path. To improve the performance, an inverse plant response filter (IPRF) is used. To improve robustness, the periodic signal model is bandwidth-limited. This limitation is largely dependent on the accuracy of the IPRF. A new method is presented for synthesizing the IPRF for discrete-time RC. The method produces filters in a simpler and more consistent manner than existing best-practice methods available in the literature, as the only variable involved is the selection of a windowing function. It is also more efficient in terms of memory and computational complexity than existing methods. Experimental results for a nanopositioning stage show that the proposed method yields the same or better tracking performance compared to existing methods. |
| 156. |  | S. A. Rios; A. J. Fleming; Y. K. Yong Design and Characterization of a Minature Monolithic Piezoelectric Hexapod Robot Inproceedings IEEE Advanced Intelligent Mechatronics, Banff, Canada, 2016. @inproceedings{C16h, title = {Design and Characterization of a Minature Monolithic Piezoelectric Hexapod Robot}, author = {S. A. Rios and A. J. Fleming and Y. K. Yong}, year = {2016}, date = {2016-07-12}, booktitle = {IEEE Advanced Intelligent Mechatronics}, address = {Banff, Canada}, abstract = {This paper describes the design, construction and resonant performance of a monolithic piezoelectric miniature hexapod robot. The miniature robot operates by driving the piezoelectric elements at the mid point between the first and second resonance modes to produce an ambulatory motion. The monolithic robot was milled out of a single piece of outwardly poled piezoelectric bimorph using an ultrasonic milling machine. Silver electrodes were evaporated onto the bimorph to isolate the individual piezoelectric elements from each other. The leg end-effectors of the robot were milled out of aluminium and a previously described lumped mass model was used to design the end-effector for the leg such that the swinging and lifting resonant modes were closely matched. The finished robot attained a swinging and lifting resonance frequency of 300 Hz and 330 Hz with a 5 Hz and 7 Hz spread between legs respectively.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This paper describes the design, construction and resonant performance of a monolithic piezoelectric miniature hexapod robot. The miniature robot operates by driving the piezoelectric elements at the mid point between the first and second resonance modes to produce an ambulatory motion. The monolithic robot was milled out of a single piece of outwardly poled piezoelectric bimorph using an ultrasonic milling machine. Silver electrodes were evaporated onto the bimorph to isolate the individual piezoelectric elements from each other. The leg end-effectors of the robot were milled out of aluminium and a previously described lumped mass model was used to design the end-effector for the leg such that the swinging and lifting resonant modes were closely matched. The finished robot attained a swinging and lifting resonance frequency of 300 Hz and 330 Hz with a 5 Hz and 7 Hz spread between legs respectively. |
| 155. |  | A. J. Fleming; G. Berriman; Y. K. Yong Design, Modeling, and Characterization of an XY Nanopositioning Stage Constructed from a Single Sheet of Piezoelectric Material Inproceedings IEEE Advanced Intelligent Mechatronics, Banff, Canada, 2016. @inproceedings{C16e, title = {Design, Modeling, and Characterization of an XY Nanopositioning Stage Constructed from a Single Sheet of Piezoelectric Material}, author = {A. J. Fleming and G. Berriman and Y. K. Yong}, year = {2016}, date = {2016-07-12}, booktitle = {IEEE Advanced Intelligent Mechatronics}, address = {Banff, Canada}, abstract = {This article describes the design, fabrication and testing of a new XY nanopositioning stage constructed from a single sheet of piezoelectric material. The approach involves direct ultrasonic machining of a piezoelectric sheet to create flexural and actuator features. An industrial inkjet printer is then used to create electrode features by printing Nitric Acid directly onto the evaporated metal surface of the piezo sheet. The result is a monolithic piezoelectric structure with individual electrical control over each actuator feature. Experimental results demonstrate a full-scale range of 9um in the X and Y axes, and a first resonance frequency of 230Hz in the Z axes. The completed nanopositioner is the thinnest yet reported with a thickness of only 500um. The new design method will enable a new range of ultra-compact applications in scanning probe microscopy, scanning electron microscopy, and active optics. }, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This article describes the design, fabrication and testing of a new XY nanopositioning stage constructed from a single sheet of piezoelectric material. The approach involves direct ultrasonic machining of a piezoelectric sheet to create flexural and actuator features. An industrial inkjet printer is then used to create electrode features by printing Nitric Acid directly onto the evaporated metal surface of the piezo sheet. The result is a monolithic piezoelectric structure with individual electrical control over each actuator feature. Experimental results demonstrate a full-scale range of 9um in the X and Y axes, and a first resonance frequency of 230Hz in the Z axes. The completed nanopositioner is the thinnest yet reported with a thickness of only 500um. The new design method will enable a new range of ultra-compact applications in scanning probe microscopy, scanning electron microscopy, and active optics. |
| 154. |  | A. J. Fleming; A. G. Wills; O. T. Ghalehbeygi; B. S. Routley; B. Ninness A Nonlinear Programming Approach to Exposure Optimization in Scanning Laser Lithography Inproceedings American Control Conference, Boston, MA, 2016. @inproceedings{C16d, title = {A Nonlinear Programming Approach to Exposure Optimization in Scanning Laser Lithography}, author = {A. J. Fleming and A. G. Wills and O. T. Ghalehbeygi and B. S. Routley and B. Ninness}, year = {2016}, date = {2016-07-01}, booktitle = {American Control Conference}, address = {Boston, MA}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 153. |  | M. R. P. Ragazzon; J. T. Gravdahl; A. J. Fleming On Amplitude Estimation for High-Speed Atomic Force Microscopy (invited) Inproceedings American Control Conference, Boston, MA, 2016. @inproceedings{C16b, title = {On Amplitude Estimation for High-Speed Atomic Force Microscopy (invited)}, author = {M. R. P. Ragazzon and J. T. Gravdahl and A. J. Fleming }, year = {2016}, date = {2016-07-01}, booktitle = {American Control Conference}, address = {Boston, MA}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 152. |  | Y. R. Teo; Y. K. Yong; A. J. Fleming A Review of Scanning Methods and Control Implications for Scanning Probe Microscopy (Invited Paper) Inproceedings American Control Conference, Boston, MA, 2016., Boston, MA, 2016. @inproceedings{C16c, title = {A Review of Scanning Methods and Control Implications for Scanning Probe Microscopy (Invited Paper)}, author = {Y. R. Teo and Y. K. Yong and A. J. Fleming}, year = {2016}, date = {2016-07-01}, booktitle = {American Control Conference, Boston, MA, 2016.}, address = {Boston, MA}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 151. |  | Y. K. Yong; S. P. Wadikhaye; A. J. Fleming High-Speed Single-Stage and Dual-Stage Mirror Scanners (Invited Paper) Inproceedings International Conference on Manipulation, Automation and Robotics at Small Scales, Paris, France, 2016. @inproceedings{C16j, title = {High-Speed Single-Stage and Dual-Stage Mirror Scanners (Invited Paper)}, author = {Y. K. Yong and S. P. Wadikhaye and A. J. Fleming}, year = {2016}, date = {2016-07-01}, booktitle = {International Conference on Manipulation, Automation and Robotics at Small Scales}, address = {Paris, France}, abstract = {This article presents a high-speed single-stage and dual-stage mirror scanner for applications in optical systems. Each scanner employs a unique end-constraint method with orthogonal flexures to preload a piezoelectric stack actuator. This end-constraint method also significantly increases the first mechanical resonance frequency. The single-stage scanner has a displacement range of 7.6 m and a first resonance frequency of 46.8 kHz. The dual-stage design consists of a long-range slow-stage and a short-range fast-stage. An inertial counterbalance technique was implemented on the fast-stage to cancel inertial forces resulting from high-speed motion. The dual-stage scanner has a combined travel range of approximately 10 m and a first resonance frequency of 130 kHz.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This article presents a high-speed single-stage and dual-stage mirror scanner for applications in optical systems. Each scanner employs a unique end-constraint method with orthogonal flexures to preload a piezoelectric stack actuator. This end-constraint method also significantly increases the first mechanical resonance frequency. The single-stage scanner has a displacement range of 7.6 m and a first resonance frequency of 46.8 kHz. The dual-stage design consists of a long-range slow-stage and a short-range fast-stage. An inertial counterbalance technique was implemented on the fast-stage to cancel inertial forces resulting from high-speed motion. The dual-stage scanner has a combined travel range of approximately 10 m and a first resonance frequency of 130 kHz. |
| 150. |  | B. S. Routley; A. J. Fleming High Sensitivity Interferometer for on-Axis Detection of AFM Cantilever Deflection Inproceedings International Conference on Manipulation, Automation and Robotics at Small Scales, Paris, France, 2016. @inproceedings{C16i, title = {High Sensitivity Interferometer for on-Axis Detection of AFM Cantilever Deflection}, author = {B. S. Routley and A. J. Fleming}, year = {2016}, date = {2016-07-01}, booktitle = {International Conference on Manipulation, Automation and Robotics at Small Scales}, address = {Paris, France}, abstract = {A homodyne path stabilised Michelson based interferometer displacement sensor was developed. This sensor achieved a noise floor of 100 fm/rt(Hz), for frequencies higher than 100 kHz. A prototype AFM that integrated this sensor was developed. Using tapping mode, topography maps of an AFM test grid were produced. }, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A homodyne path stabilised Michelson based interferometer displacement sensor was developed. This sensor achieved a noise floor of 100 fm/rt(Hz), for frequencies higher than 100 kHz. A prototype AFM that integrated this sensor was developed. Using tapping mode, topography maps of an AFM test grid were produced. |
| 149. |  | A. J. Fleming; K. K. Leang Position Sensors for Nanopositioning Book Chapter Ru, C; Liu, X; Sun, Y (Ed.): Springer, 2016, ISBN: 978-3-319-23853-1. @inbook{B15a, title = {Position Sensors for Nanopositioning}, author = {A. J. Fleming and K. K. Leang}, editor = {C. Ru and X. Liu and Y. Sun}, isbn = {978-3-319-23853-1}, year = {2016}, date = {2016-02-01}, publisher = {Springer}, abstract = {Position sensors with nanometer resolution are a key component of many precision imaging and fabrication machines. Since the sensor characteristics can define the linearity, resolution and speed of the machine, the sensor performance is a foremost consideration. The first goal of this article is to define concise performance metrics and to provide exact and approximate expressions for error sources including non-linearity, drift and noise. The second goal is to review current position sensor technologies and to compare their performance. The sensors considered include: resistive, piezoelectric and piezoresistive strain sensors; capacitive sensors; electrothermal sensors; eddy current sensors; linear variable displacement transformers; interferometers; and linear encoders.}, keywords = {}, pubstate = {published}, tppubtype = {inbook} } Position sensors with nanometer resolution are a key component of many precision imaging and fabrication machines. Since the sensor characteristics can define the linearity, resolution and speed of the machine, the sensor performance is a foremost consideration. The first goal of this article is to define concise performance metrics and to provide exact and approximate expressions for error sources including non-linearity, drift and noise. The second goal is to review current position sensor technologies and to compare their performance. The sensors considered include: resistive, piezoelectric and piezoresistive strain sensors; capacitive sensors; electrothermal sensors; eddy current sensors; linear variable displacement transformers; interferometers; and linear encoders. |
| 148. |  | K. K. Leang; A. J. Fleming Tracking Control for Nanopositioning Systems Book Chapter Ru, C; Liu, X; Sun, Y (Ed.): Springer, 2016, ISBN: 978-3-319-23853-1. @inbook{B15b, title = {Tracking Control for Nanopositioning Systems}, author = {K. K. Leang and A. J. Fleming}, editor = {C. Ru and X. Liu and Y. Sun}, isbn = {978-3-319-23853-1}, year = {2016}, date = {2016-02-01}, publisher = {Springer}, abstract = {The performance of nanopositioning systems is greatly affected by their mechanical dynamics, and for piezo-actuated designs, induced structural vibration, hysteresis, and creep can drastically limit positioning precision. Therefore, tracking control, both feedback and feedforward control, plays an important role in achieving high-performance operation, especially at high operating frequencies. This chapter reviews popular feedback and feedforward control techniques for nanopositioning systems. First, the effects of vibration, hysteresis, and creep are described, where simple methods traditionally employed to avoid these effects are discussed. Second, various models for nanopositioning systems for control system design, simulation, and synthesis are presented. Finally, popular feedback and feedforward controllers to handle vibration, hysteresis, and creep are presented, along with experimental results.}, keywords = {}, pubstate = {published}, tppubtype = {inbook} } The performance of nanopositioning systems is greatly affected by their mechanical dynamics, and for piezo-actuated designs, induced structural vibration, hysteresis, and creep can drastically limit positioning precision. Therefore, tracking control, both feedback and feedforward control, plays an important role in achieving high-performance operation, especially at high operating frequencies. This chapter reviews popular feedback and feedforward control techniques for nanopositioning systems. First, the effects of vibration, hysteresis, and creep are described, where simple methods traditionally employed to avoid these effects are discussed. Second, various models for nanopositioning systems for control system design, simulation, and synthesis are presented. Finally, popular feedback and feedforward controllers to handle vibration, hysteresis, and creep are presented, along with experimental results. |
| 147. |  | S. A. Rios; A. J. Fleming Design of a Charge Drive for Reducing Hysteresis in a Piezoelectric Bimorph Actuator Journal Article IEEE/ASME Transactions on Mechatronics, 21 (1), pp. 51-54, 2016. @article{J16f, title = {Design of a Charge Drive for Reducing Hysteresis in a Piezoelectric Bimorph Actuator}, author = {S. A. Rios and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/01/J16f.pdf}, doi = {10.1109/TMECH.2015.2483739}, year = {2016}, date = {2016-02-01}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {21}, number = {1}, pages = {51-54}, abstract = {This article describes the design of a charge drive for reducing the hysteresis exhibited by a piezoelectric bimorph bender. Existing charge drive circuits cannot be directly applied to bimorph benders since they share a common electrode. In this article a new charge drive circuit and electrical configuration is implemented that allows commonly available piezoelectric bimorphs to be linearized. This circuit consists of four major components, including, a high voltage amplifier, a differential amplifier, a piezoelectric load and a PI feedback controller. An isolation amplifier was used to achieve a differential amplifier with a high common-mode rejection ratio. The charge drive was tested by driving a series poled, three layer bimorph bender. The results demonstrate that the use of a charge drive can reduce the hysteresis from 26.8% to 2.1%. This work has identified an alternative feedforward method to improve the AC hysteresis performance of a piezoelectric bender by using a charge drive.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article describes the design of a charge drive for reducing the hysteresis exhibited by a piezoelectric bimorph bender. Existing charge drive circuits cannot be directly applied to bimorph benders since they share a common electrode. In this article a new charge drive circuit and electrical configuration is implemented that allows commonly available piezoelectric bimorphs to be linearized. This circuit consists of four major components, including, a high voltage amplifier, a differential amplifier, a piezoelectric load and a PI feedback controller. An isolation amplifier was used to achieve a differential amplifier with a high common-mode rejection ratio. The charge drive was tested by driving a series poled, three layer bimorph bender. The results demonstrate that the use of a charge drive can reduce the hysteresis from 26.8% to 2.1%. This work has identified an alternative feedforward method to improve the AC hysteresis performance of a piezoelectric bender by using a charge drive. |
2015 |
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| 146. |  | A. J. Fleming; B. S. Routley A Closed-Loop Phase-Locked Interferometer for Wide Bandwidth Position Sensing Journal Article Review of Scientific Instruments, 86 , pp. 115001(1-7), 2015. @article{J15f, title = {A Closed-Loop Phase-Locked Interferometer for Wide Bandwidth Position Sensing}, author = {A. J. Fleming and B. S. Routley}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/12/J15f.pdf}, doi = {10.1063/1.4935469}, year = {2015}, date = {2015-12-31}, journal = {Review of Scientific Instruments}, volume = {86}, pages = {115001(1-7)}, abstract = {This article describes a position sensitive interferometer with closed-loop control of the reference mirror. A calibrated nanopositioner is used to lock the interferometer phase to the most sensitive point in the interfer- ogram. In this con guration, large low-frequency movements of the sensor mirror can be detected from the control signal applied to the nanopositioner and high-frequency short-range signals can be measured directly from the photodiode. It is demonstrated that these two signals are complementary and can be summed to find the total displacement. The resulting interferometer has a number of desirable characteristics: it is optically simple, does not require polarization or modulation to detect the direction of motion, does not require fringe-counting or interpolation electronics, and has a bandwidth equal to that of the photodiode. Experimental results demonstrate the frequency response analysis of a high-speed positioning stage. The proposed instru- ment is ideal for measuring the frequency response of nanopositioners, electro-optical components, MEMs devices, Ultrasonic devices, and sensors such as surface acoustic wave detectors.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article describes a position sensitive interferometer with closed-loop control of the reference mirror. A calibrated nanopositioner is used to lock the interferometer phase to the most sensitive point in the interfer- ogram. In this con guration, large low-frequency movements of the sensor mirror can be detected from the control signal applied to the nanopositioner and high-frequency short-range signals can be measured directly from the photodiode. It is demonstrated that these two signals are complementary and can be summed to find the total displacement. The resulting interferometer has a number of desirable characteristics: it is optically simple, does not require polarization or modulation to detect the direction of motion, does not require fringe-counting or interpolation electronics, and has a bandwidth equal to that of the photodiode. Experimental results demonstrate the frequency response analysis of a high-speed positioning stage. The proposed instru- ment is ideal for measuring the frequency response of nanopositioners, electro-optical components, MEMs devices, Ultrasonic devices, and sensors such as surface acoustic wave detectors. |
| 145. |  | D. Russell; A. J. Fleming; S. S. Aphale Journal of Dynamic Systems, Measurement and Control, 137 (10), pp. 1-8, 2015. @article{J15b, title = {Simultaneous Optimization of Damping and Tracking Controller Parameters via Selective Pole Placement for Enhanced Positioning Bandwidth of Nanopositioners}, author = {D. Russell and A. J. Fleming and S. S. Aphale}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/07/DS-14-1539.pdf}, doi = {10.1115/1.4030723}, year = {2015}, date = {2015-12-30}, journal = {Journal of Dynamic Systems, Measurement and Control}, volume = {137}, number = {10}, pages = {1-8}, abstract = {Positive Velocity and Position Feedback (PVPF) is a widely used control scheme in lightly damped resonant systems with collocated sensor actuator pairs. The popularity of PVPF is due to the ability to achieve a chosen damping ratio by repositioning the poles of the system. The addition of a tracking controller, to reduce the effects of inherent nonlinearities, causes the poles to deviate from the intended location and can be a detriment to the damping achieved. By designing the PVPF and tracking controllers simultaneously, the optimal damping and tracking can be achieved. Simulations show full damping of the first resonance mode and significantly higher bandwidth than that achieved using the traditional PVPF design method, allowing for high speed scanning with accurate tracking. Experimental results are also provided to verify performance in implementation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Positive Velocity and Position Feedback (PVPF) is a widely used control scheme in lightly damped resonant systems with collocated sensor actuator pairs. The popularity of PVPF is due to the ability to achieve a chosen damping ratio by repositioning the poles of the system. The addition of a tracking controller, to reduce the effects of inherent nonlinearities, causes the poles to deviate from the intended location and can be a detriment to the damping achieved. By designing the PVPF and tracking controllers simultaneously, the optimal damping and tracking can be achieved. Simulations show full damping of the first resonance mode and significantly higher bandwidth than that achieved using the traditional PVPF design method, allowing for high speed scanning with accurate tracking. Experimental results are also provided to verify performance in implementation. |
| 144. |  | A. J. Fleming; Y. R. Teo; K. K. Leang Low-order Damping and Tracking Control for Scanning Probe Systems Journal Article Frontiers in Mechanical Engineering, 1 , pp. 1-9, 2015. @article{J15e, title = {Low-order Damping and Tracking Control for Scanning Probe Systems}, author = {A. J. Fleming and Y. R. Teo and K. K. Leang }, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/12/J15e.pdf}, doi = {10.3389/fmech.2015.00014}, year = {2015}, date = {2015-12-30}, journal = {Frontiers in Mechanical Engineering}, volume = {1}, pages = {1-9}, abstract = {This article describes an improvement to integral resonance damping control (IRC) for reference tracking applications such as Scanning Probe Microscopy and nanofabrication. It is demonstrated that IRC control introduces a low-frequency pole into the tracking loop which is detrimental for performance. In this work, the location of this pole is found analytically using Cardano’s method then compensated by parameterizing the tracking controller accordingly. This approach maximizes the closed-loop bandwidth whilst being robust to changes in the resonance frequencies. The refined IRC controller is comprehensively compared to other low-order methods in a practical environment.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article describes an improvement to integral resonance damping control (IRC) for reference tracking applications such as Scanning Probe Microscopy and nanofabrication. It is demonstrated that IRC control introduces a low-frequency pole into the tracking loop which is detrimental for performance. In this work, the location of this pole is found analytically using Cardano’s method then compensated by parameterizing the tracking controller accordingly. This approach maximizes the closed-loop bandwidth whilst being robust to changes in the resonance frequencies. The refined IRC controller is comprehensively compared to other low-order methods in a practical environment. |
| 143. |  | S. A. Rios; A. J. Fleming A New Electrical Configuration for Improving the Range of Piezoelectric Bimorph Benders Journal Article Sensors and Actuators A: Physical, 224 , pp. 106-110, 2015. @article{J15a, title = {A New Electrical Configuration for Improving the Range of Piezoelectric Bimorph Benders}, author = {S. A. Rios and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/04/J15a3.pdf}, year = {2015}, date = {2015-12-01}, journal = {Sensors and Actuators A: Physical}, volume = {224}, pages = {106-110}, abstract = {This article describes a new electrical configuration for driving piezoelectric benders. The ‘Biased Bipolar’ configuration is compatible with parallel-polled, bimorph and multimorph benders. The new configuration is similar to the standard three-wire drive method where the top electrode is biased with a DC voltage and the bottom electrode is grounded. However, the new configuration uses an alternate DC bias voltage and adjusted range for the central electrode which allows the full range of positive and negative electric fields to be utilized. Using this technique, the predicted deflection and force can be increased by a factor of 2.2 compared to the standard two wire configuration and 1.3 times for the standard three wire configuration. These predictions were verified experimentally where the measured factor of improvement in displacement and force was of 2.4 and 1.3 compared to the standard two-wire and three-wire configurations.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article describes a new electrical configuration for driving piezoelectric benders. The ‘Biased Bipolar’ configuration is compatible with parallel-polled, bimorph and multimorph benders. The new configuration is similar to the standard three-wire drive method where the top electrode is biased with a DC voltage and the bottom electrode is grounded. However, the new configuration uses an alternate DC bias voltage and adjusted range for the central electrode which allows the full range of positive and negative electric fields to be utilized. Using this technique, the predicted deflection and force can be increased by a factor of 2.2 compared to the standard two wire configuration and 1.3 times for the standard three wire configuration. These predictions were verified experimentally where the measured factor of improvement in displacement and force was of 2.4 and 1.3 compared to the standard two-wire and three-wire configurations. |
| 142. |  | A. J. Fleming; B. S. Routley; J. L. Holdsworth A Closed-Loop Phase-Locked Interferometer for Wide Bandwidth Position Sensing Inproceedings IEEE Multi-conference on Systems and Control, Sydney, 2015. @inproceedings{C15a, title = {A Closed-Loop Phase-Locked Interferometer for Wide Bandwidth Position Sensing}, author = {A. J. Fleming and B. S. Routley and J. L. Holdsworth}, year = {2015}, date = {2015-12-01}, booktitle = {IEEE Multi-conference on Systems and Control}, address = {Sydney}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 141. |  | O. T. Ghalehbeygi; G. Berriman; A. J. Fleming; J. L. Holdsworth Optimization and Simulation of Exposure Pattern for Scanning Laser Lithography Inproceedings IEEE Multiconference on Systems and Control, Sydney, 2015. @inproceedings{C15d, title = {Optimization and Simulation of Exposure Pattern for Scanning Laser Lithography}, author = {O. T. Ghalehbeygi and G. Berriman and A. J. Fleming and J. L. Holdsworth}, year = {2015}, date = {2015-12-01}, booktitle = {IEEE Multiconference on Systems and Control}, address = {Sydney}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 140. |  | T. D. Godfrey; A. A. Eielsen; A. J. Fleming Digital to Analog Converter Considerations for Achieving One Part-Per-Million in Precision Mechatronics Systems Inproceedings IEEE Multiconference on Systems and Control, Sydney, 2015. @inproceedings{C15f, title = {Digital to Analog Converter Considerations for Achieving One Part-Per-Million in Precision Mechatronics Systems}, author = {T. D. Godfrey and A. A. Eielsen and A. J. Fleming}, year = {2015}, date = {2015-12-01}, booktitle = {IEEE Multiconference on Systems and Control}, address = {Sydney}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 139. |  | Y. R. Teo; A. A. Eielsen; A. J. Fleming Model-less FIR Repetitive Control with consideration of uncertainty Inproceedings IEEE Multiconference on Systems and Control, Sydney, 2015. @inproceedings{C15c, title = {Model-less FIR Repetitive Control with consideration of uncertainty}, author = {Y. R. Teo and A. A. Eielsen and A. J. Fleming}, year = {2015}, date = {2015-12-01}, booktitle = {IEEE Multiconference on Systems and Control}, address = {Sydney}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 138. |  | S. A. Rios; A. J. Fleming; Y. K. Yong Design of a two degree of freedom resonant miniature robotic leg (Invited Paper) Inproceedings IEEE Advanced Intelligent Mechatronics, Busan, Korea, 2015. @inproceedings{C15b, title = {Design of a two degree of freedom resonant miniature robotic leg (Invited Paper)}, author = {S. A. Rios and A. J. Fleming and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/05/Design-of-a-two-DoF-resonant-miniature-robotic-leg_DRAFT003.pdf}, year = {2015}, date = {2015-07-01}, booktitle = {IEEE Advanced Intelligent Mechatronics}, address = {Busan, Korea}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 137. |  | Y. R. Teo; A. J. Fleming Optimal integral force feedback for active vibration control Journal Article Journal of Sound and Vibration, 356 (11), pp. 20-33, 2015. @article{J15c, title = {Optimal integral force feedback for active vibration control}, author = {Y. R. Teo and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/10/J15c.pdf}, year = {2015}, date = {2015-06-27}, journal = {Journal of Sound and Vibration}, volume = {356}, number = {11}, pages = {20-33}, abstract = {This paper proposes an improvement to Integral Force Feedback (IFF), which is a popular method for active vibration control for structures and mechanical systems. Benefits of IFF includes robustness, guaranteed stability and simplicity. However, the maximum damping performance is dependent on the stiffness of the system; hence, some systems cannot be adequately controlled. In this paper, an improvement to the classical force feedback control scheme is proposed. The improved method achieves arbitrary damping for any mechanical system by introducing a feed-through term. The proposed improvement is experimentally demonstrated by actively damping an objective lens assembly for a high-speed confocal microscope.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper proposes an improvement to Integral Force Feedback (IFF), which is a popular method for active vibration control for structures and mechanical systems. Benefits of IFF includes robustness, guaranteed stability and simplicity. However, the maximum damping performance is dependent on the stiffness of the system; hence, some systems cannot be adequately controlled. In this paper, an improvement to the classical force feedback control scheme is proposed. The improved method achieves arbitrary damping for any mechanical system by introducing a feed-through term. The proposed improvement is experimentally demonstrated by actively damping an objective lens assembly for a high-speed confocal microscope. |
| 136. |  | A. J. Fleming; Y. K. Yong Piezoelectric Actuators with Integrated High Voltage Power Electronics Journal Article IEEE/ASME Transactions on Mechatronics, 20 (2), pp. 611-617, 2015. @article{J14b, title = {Piezoelectric Actuators with Integrated High Voltage Power Electronics}, author = {A. J. Fleming and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/10/J14b.pdf}, year = {2015}, date = {2015-04-01}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {20}, number = {2}, pages = {611-617}, abstract = {This article explores the possibility of piezoelectric actuators with integrated high voltage power electronics. Such devices dramatically simplify the application of piezoelectric actuators since the power electronics are already optimized for the voltage range, capacitance, and power dissipation of the actuator. The foremost consideration is the thermal impedance of the actuator and heat dissipation. Analytical and finite-element methods are described for predicting the thermal impedance of a piezoelectric bender. The predictions are compared experimentally using thermal imaging on a piezoelectric bender with laminated miniature power electronics.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article explores the possibility of piezoelectric actuators with integrated high voltage power electronics. Such devices dramatically simplify the application of piezoelectric actuators since the power electronics are already optimized for the voltage range, capacitance, and power dissipation of the actuator. The foremost consideration is the thermal impedance of the actuator and heat dissipation. Analytical and finite-element methods are described for predicting the thermal impedance of a piezoelectric bender. The predictions are compared experimentally using thermal imaging on a piezoelectric bender with laminated miniature power electronics. |
| 135. |  | B. S. Routley; J. L. Holdsworth; A. J. Fleming Optimization of near-field scanning optical lithography Inproceedings Proc. SPIE Advanced Lithography, San Jose, CA, 2015. @inproceedings{D15a, title = {Optimization of near-field scanning optical lithography}, author = {B. S. Routley and J. L. Holdsworth and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/05/D15a.pdf}, year = {2015}, date = {2015-02-26}, booktitle = {Proc. SPIE Advanced Lithography}, address = {San Jose, CA}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
2014 |
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| 134. |  | A. J. Fleming; K. K. Leang Design, Modeling and Control of Nanopositioning Systems Book Springer, London, UK, 2014, ISBN: 978-3319066165. @book{B14, title = {Design, Modeling and Control of Nanopositioning Systems}, author = {A. J. Fleming and K. K. Leang}, url = {http://www.amazon.com/Modeling-Control-Nanopositioning-Advances-Industrial/dp/3319066161 }, isbn = {978-3319066165}, year = {2014}, date = {2014-12-30}, publisher = {Springer}, address = {London, UK}, abstract = {Covering the complete design cycle of nanopositioning systems, this is the first comprehensive text on the topic. The book first introduces concepts associated with nanopositioning stages and outlines their application in such tasks as scanning probe microscopy, nanofabrication, data storage, cell surgery and precision optics. Piezoelectric transducers, employed ubiquitously in nanopositioning applications are then discussed in detail including practical considerations and constraints on transducer response. The reader is then given an overview of the types of nanopositioner before the text turns to the in-depth coverage of mechanical design including flexures, materials, manufacturing techniques, and electronics. This process is illustrated by the example of a high-speed serial-kinematic nanopositioner. Position sensors are then catalogued and described and the text then focuses on control. Several forms of control are treated: shunt control, feedback control, force feedback control and feedforward control (including an appreciation of iterative learning control). Performance issues are given importance as are problems limiting that performance such as hysteresis and noise which arise in the treatment of control and are then given chapter-length attention in their own right. The reader also learns about cost functions and other issues involved in command shaping, charge drives and electrical considerations. All concepts are demonstrated experimentally including by direct application to atomic force microscope imaging. Design, Modeling and Control of Nanopositioning Systems will be of interest to researchers in mechatronics generally and in control applied to atomic force microscopy and other nanopositioning applications. Microscope developers and mechanical designers of nanopositioning devices will find the text essential reading.}, keywords = {}, pubstate = {published}, tppubtype = {book} } Covering the complete design cycle of nanopositioning systems, this is the first comprehensive text on the topic. The book first introduces concepts associated with nanopositioning stages and outlines their application in such tasks as scanning probe microscopy, nanofabrication, data storage, cell surgery and precision optics. Piezoelectric transducers, employed ubiquitously in nanopositioning applications are then discussed in detail including practical considerations and constraints on transducer response. The reader is then given an overview of the types of nanopositioner before the text turns to the in-depth coverage of mechanical design including flexures, materials, manufacturing techniques, and electronics. This process is illustrated by the example of a high-speed serial-kinematic nanopositioner. Position sensors are then catalogued and described and the text then focuses on control. Several forms of control are treated: shunt control, feedback control, force feedback control and feedforward control (including an appreciation of iterative learning control). Performance issues are given importance as are problems limiting that performance such as hysteresis and noise which arise in the treatment of control and are then given chapter-length attention in their own right. The reader also learns about cost functions and other issues involved in command shaping, charge drives and electrical considerations. All concepts are demonstrated experimentally including by direct application to atomic force microscope imaging. Design, Modeling and Control of Nanopositioning Systems will be of interest to researchers in mechatronics generally and in control applied to atomic force microscopy and other nanopositioning applications. Microscope developers and mechanical designers of nanopositioning devices will find the text essential reading. |
| 133. |  | M. Namavar; A. J. Fleming; M. Aleyaasin; K. Nakkeeran; S. S. Aphale An Analytical approach to integral resonant control of second-order systems Journal Article IEEE/ASME Transactions on Mechatronics, 19 (2), pp. 651–659, 2014. @article{J14c, title = {An Analytical approach to integral resonant control of second-order systems}, author = {M. Namavar and A. J. Fleming and M. Aleyaasin and K. Nakkeeran and S. S. Aphale}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2014/05/J14c.pdf}, year = {2014}, date = {2014-12-01}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {19}, number = {2}, pages = {651--659}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 132. |  | A. J. Fleming Measuring and predicting resolution in nanopositioning systems Journal Article Mechatronics, 24 (8), pp. 605-618, 2014. @article{J14a, title = {Measuring and predicting resolution in nanopositioning systems}, author = {A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2014/09/J14a.pdf}, year = {2014}, date = {2014-12-01}, journal = {Mechatronics}, volume = {24}, number = {8}, pages = {605-618}, abstract = {The resolution is a critical performance metric of precision mechatronic systems such as nanopositioners and atomic force microscopes. However, there is not presently a strict definition for the measurement or reporting of this parameter. This article defines resolution as the smallest distance between two nonoverlapping position commands. Methods are presented for simulating and predicting resolution in both the time and frequency domains. In order to simplify resolution measurement, a new technique is proposed which allows the resolution to be estimated from a measurement of the closed-loop actuator voltage. Simulation and experimental results demonstrate the proposed techniques. The paper concludes by comparing the resolution benefits of new control schemes over standard output feedback techniques.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The resolution is a critical performance metric of precision mechatronic systems such as nanopositioners and atomic force microscopes. However, there is not presently a strict definition for the measurement or reporting of this parameter. This article defines resolution as the smallest distance between two nonoverlapping position commands. Methods are presented for simulating and predicting resolution in both the time and frequency domains. In order to simplify resolution measurement, a new technique is proposed which allows the resolution to be estimated from a measurement of the closed-loop actuator voltage. Simulation and experimental results demonstrate the proposed techniques. The paper concludes by comparing the resolution benefits of new control schemes over standard output feedback techniques. |
| 131. |  | Y. R. Teo; D. Russell; S. S. Aphale; A. J. Fleming Optimal Integral Force Feedback and Structured PI Tracking Control: Application for High Speed Confocal Microscopy Journal Article Mechatronics, 24 (6), pp. 701-711, 2014. @article{J14d, title = {Optimal Integral Force Feedback and Structured PI Tracking Control: Application for High Speed Confocal Microscopy}, author = {Y. R. Teo and D. Russell and S. S. Aphale and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2014/09/J14d.pdf}, year = {2014}, date = {2014-12-01}, journal = {Mechatronics}, volume = {24}, number = {6}, pages = {701-711}, abstract = {This paper describes a new vibration damping technique based on Integral Force Feedback (IFF). Classical IFF utilizes a force sensor and integral controller to damp the resonance modes of a mechanical system. However, the maximum modal damping depends on the frequency difference between the system’s poles and zeros. If the frequency difference is small, the achievable modal damping may be severely limited. The proposed technique allows an arbitrary damping ratio to be achieved by introducing an additional feed-through term to the control system. This results in an extra degree of freedom that allows the position of the zeros to be modified and the maximum modal damping to be increased. The second contribution of this paper is a structured PI tracking controller that is parameterized to cancel the additional pole introduced by integral force feedback. The parameterized controller has only one tuning parameter and does not suffer from reduced phase margin. The proposed techniques are demonstrated on a piezoelectric objective lens positioner. The results show exceptional tracking and damping performance while maintaining insensitivity to changes in resonance frequency. The maximum bandwidth achievable with a commercial PID controller is 26.1 Hz. In contrast, with the proposed damping and tracking controller, the bandwidth is increased to 255 Hz.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper describes a new vibration damping technique based on Integral Force Feedback (IFF). Classical IFF utilizes a force sensor and integral controller to damp the resonance modes of a mechanical system. However, the maximum modal damping depends on the frequency difference between the system’s poles and zeros. If the frequency difference is small, the achievable modal damping may be severely limited. The proposed technique allows an arbitrary damping ratio to be achieved by introducing an additional feed-through term to the control system. This results in an extra degree of freedom that allows the position of the zeros to be modified and the maximum modal damping to be increased. The second contribution of this paper is a structured PI tracking controller that is parameterized to cancel the additional pole introduced by integral force feedback. The parameterized controller has only one tuning parameter and does not suffer from reduced phase margin. The proposed techniques are demonstrated on a piezoelectric objective lens positioner. The results show exceptional tracking and damping performance while maintaining insensitivity to changes in resonance frequency. The maximum bandwidth achievable with a commercial PID controller is 26.1 Hz. In contrast, with the proposed damping and tracking controller, the bandwidth is increased to 255 Hz. |
| 130. |  | M. N. Islam; A. J. Fleming A Novel and Compatible Sensing Coil for a Capsule in Wireless Capsule Endoscopy for Real Time Localization Inproceedings IEEE Sensors, Valencia, Spain, 2014. @inproceedings{C14h, title = {A Novel and Compatible Sensing Coil for a Capsule in Wireless Capsule Endoscopy for Real Time Localization}, author = {M. N. Islam and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/05/C14h.pdf}, year = {2014}, date = {2014-11-02}, booktitle = {IEEE Sensors}, address = {Valencia, Spain}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 129. |  | D. Russell; A. J. Fleming; S. S. Aphale Improving the positioning bandwidth of the Integral Resonant Control Scheme through strategic zero placement Inproceedings Proc. IFAC World Congress, Cape Town, South Africa, 2014. @inproceedings{C14e, title = {Improving the positioning bandwidth of the Integral Resonant Control Scheme through strategic zero placement}, author = {D. Russell and A. J. Fleming and S. S. Aphale}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/05/C14e.pdf}, year = {2014}, date = {2014-09-01}, booktitle = {Proc. IFAC World Congress}, address = {Cape Town, South Africa}, crossref = {(Invited Session)}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 128. |  | Y. R. Teo; D. Russell; S. S. Aphale; A. J. Fleming Optimal Integral Force Feedback and Structured PI Tracking Control: Application for High Speed Confocal Microscopy Inproceedings Proc. IFAC World Congress, Cape Town, South Africa, 2014. @inproceedings{C14d, title = {Optimal Integral Force Feedback and Structured PI Tracking Control: Application for High Speed Confocal Microscopy}, author = {Y. R. Teo and D. Russell and S. S. Aphale and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/05/C14d.pdf}, year = {2014}, date = {2014-09-01}, booktitle = {Proc. IFAC World Congress}, address = {Cape Town, South Africa}, crossref = {(Invited Session)}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 127. |  | S. A. Rios; A. J. Fleming A Novel Electrical Configuration for Three Wire Piezoelectric Bimorph Micro-Positioners Inproceedings Proc. IEEE/ASME Advanced Intelligent Mechatronics, Besançon, France, 2014. @inproceedings{C14g, title = {A Novel Electrical Configuration for Three Wire Piezoelectric Bimorph Micro-Positioners}, author = {S. A. Rios and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/05/C14g.pdf}, year = {2014}, date = {2014-06-30}, booktitle = {Proc. IEEE/ASME Advanced Intelligent Mechatronics}, address = {Besançon, France}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 126. |  | Y. R. Teo; A. A. Eielsen; J. T. Gravdahl; A. J. Fleming Discrete-time repetitive control with model-less FIR filter inversion for high performance nanopositioning Inproceedings Proc. IEEE/ASME Advanced Intelligent Mechatronics, Besançon, France, 2014. @inproceedings{C14f, title = {Discrete-time repetitive control with model-less FIR filter inversion for high performance nanopositioning}, author = {Y. R. Teo and A. A. Eielsen and J. T. Gravdahl and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/05/C14f1.pdf}, year = {2014}, date = {2014-06-30}, booktitle = {Proc. IEEE/ASME Advanced Intelligent Mechatronics}, address = {Besançon, France}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 125. |  | S. A. Rios; A. J. Fleming Control of Piezoelectric Benders Using a Charge Drive Inproceedings Proc. Actuator, Bremen, 2014. @inproceedings{D14a, title = {Control of Piezoelectric Benders Using a Charge Drive}, author = {S. A. Rios and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/05/D14a1.pdf}, year = {2014}, date = {2014-06-20}, booktitle = {Proc. Actuator}, address = {Bremen}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 124. |  | Y. R. Teo; A. J. Fleming Active Damping Control Using Optimal Integral Force Feedback Inproceedings Proc. American Control Conference, Portland, Oregon, 2014. @inproceedings{C14c, title = {Active Damping Control Using Optimal Integral Force Feedback}, author = {Y. R. Teo and A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/05/C14c.pdf}, year = {2014}, date = {2014-06-02}, booktitle = {Proc. American Control Conference}, address = {Portland, Oregon}, crossref = {(Invited Session)}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 123. |  | Y. R. Teo; A. J. Fleming A New Repetitive Control Scheme Based on Non-Causal FIR Filters Inproceedings Proc. American Control Conference, Portland, Oregon, 2014. @inproceedings{C14b, title = {A New Repetitive Control Scheme Based on Non-Causal FIR Filters}, author = {Y. R. Teo and A. J. Fleming }, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/05/C14b1.pdf}, year = {2014}, date = {2014-06-02}, booktitle = {Proc. American Control Conference}, address = {Portland, Oregon}, crossref = {(Invited Session)}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 122. |  | D. Russell; A. J. Fleming; S. S. Aphale Proc. American Control Conference, Portland, Oregon, 2014. @inproceedings{C14a, title = {Simultaneous Optimization of Damping and Tracking Controller Parameters via Selective Pole Placement for Enhanced positioning Bandwidth of Nanopositioners}, author = {D. Russell and A. J. Fleming and S. S. Aphale}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2015/05/C14a1.pdf}, year = {2014}, date = {2014-06-02}, booktitle = {Proc. American Control Conference}, address = {Portland, Oregon}, crossref = {(Invited Session)}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
2013 |
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| 121. |  | A. J. Fleming A review of nanometer resolution position sensors: operation and performance Journal Article Sensors and Actuators A: Physical, 190 , pp. 106-126, 2013. @article{J13a, title = {A review of nanometer resolution position sensors: operation and performance}, author = {A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/J13a.pdf}, year = {2013}, date = {2013-12-01}, journal = {Sensors and Actuators A: Physical}, volume = {190}, pages = {106-126}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 120. |  | Y. K. Yong; A. J. Fleming; S. O. R. Moheimani A novel piezoelectric strain sensor for simultaneous damping and tracking control of a high-speed nanopositioner Journal Article IEEE/ASME Transactions on Mechatronics, 18 (3), pp. 1113-1121, 2013. @article{J13b, title = {A novel piezoelectric strain sensor for simultaneous damping and tracking control of a high-speed nanopositioner}, author = {Y. K. Yong and A. J. Fleming and S. O. R. Moheimani}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/J13b.pdf}, year = {2013}, date = {2013-12-01}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {18}, number = {3}, pages = {1113-1121}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 119. |  | A. J. Fleming Charge drive with active DC stabilization for linearization of piezoelectric hysteresis Journal Article IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 60 (8), 2013. @article{J13d, title = {Charge drive with active DC stabilization for linearization of piezoelectric hysteresis}, author = {A. J. Fleming}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/J13d.pdf}, year = {2013}, date = {2013-12-01}, journal = {IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control}, volume = {60}, number = {8}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 118. |  | A. J. Fleming; B. Ninness; A. G. Wills Recovering the spectrum of a low level signal from two noisy measurements using the cross power spectral density Journal Article Review of Scientific Instruments, 84 , pp. 085112, 6 pages, 2013. @article{J13e, title = {Recovering the spectrum of a low level signal from two noisy measurements using the cross power spectral density}, author = {A. J. Fleming and B. Ninness and A. G. Wills}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/J13e.pdf}, year = {2013}, date = {2013-12-01}, journal = {Review of Scientific Instruments}, volume = {84}, pages = {085112, 6 pages}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 117. |  | S. A. Rios; A. J. Fleming Systems and Methods for Driving Piezoelectric Benders Miscellaneous Patent, 2013. @misc{P5, title = {Systems and Methods for Driving Piezoelectric Benders}, author = {S. A. Rios and A. J. Fleming}, year = {2013}, date = {2013-11-01}, howpublished = {Patent}, keywords = {}, pubstate = {published}, tppubtype = {misc} } |
| 116. |  | A. J. Fleming Precision charge drive with low frequency voltage feedback for linearization of piezoelectric hysteresis Inproceedings Proc. IEEE American Control Conference, Washington, DC, 2013. @inproceedings{C13a, title = {Precision charge drive with low frequency voltage feedback for linearization of piezoelectric hysteresis}, author = {A. J. Fleming}, year = {2013}, date = {2013-01-01}, booktitle = {Proc. IEEE American Control Conference}, address = {Washington, DC}, crossref = {(Invited Session)}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 115. |  | A. J. Fleming; K. K. Leang An Experimental Comparison of PI, Inversion, and Damping Control for High Performance Nanopositioning Inproceedings Proc. IEEE American Control Conference, Washington, DC, 2013. @inproceedings{C13b, title = {An Experimental Comparison of PI, Inversion, and Damping Control for High Performance Nanopositioning}, author = {A. J. Fleming and K. K. Leang}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/C13b.pdf}, year = {2013}, date = {2013-01-01}, booktitle = {Proc. IEEE American Control Conference}, address = {Washington, DC}, crossref = {(Invited Session)}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
| 114. |  | A. J. Fleming Position Sensor Performance in Nanometer Resolution Feedback Systems Inproceedings Proc. IFAC Symposium on Mechatronic Systems, Hangzhou, China, 2013. @inproceedings{C13c, title = {Position Sensor Performance in Nanometer Resolution Feedback Systems}, author = {A. J. Fleming}, year = {2013}, date = {2013-01-01}, booktitle = {Proc. IFAC Symposium on Mechatronic Systems}, address = {Hangzhou, China}, crossref = {(Invited Session)}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |