Acoustics AFM Biomedical Cantilever DACs Demodulation Energy based control Lithography MEMS Multifrequency AFM Nanopositioning Optics patent Piezoelectric Transducers and Drives Robotics Scan Pattern Sensors Smart Structures SPM System Identification Tracking Control Vibration Control
2019 | ||
| 22. |  | 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 (Inproceeding) International Conference on Manipulation, Automation and Robotics at Small Scales (MARSS), Helsinki, Finland, 2019. (Abstract | BibTeX | Tags: Nanopositioning, Tracking Control, Vibration Control) @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 = {Nanopositioning, Tracking Control, Vibration Control}, 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. |
| 21. |  | M. G. Ruppert, B. S. Routley, A. J. Fleming, Y. K. Yong, G. E. Fantner Model-based Q Factor Control for Photothermally Excited Microcantilevers (Inproceeding) Int. Conference on Manipulation, Automation and Robotics at Small Scales (MARSS), Helsinki, Finland, 2019. (Abstract | BibTeX | Tags: AFM, Multifrequency AFM, Sensors, Smart Structures, SPM, Vibration Control) @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 = {AFM, Multifrequency AFM, Sensors, Smart Structures, SPM, Vibration Control}, 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. |
2018 | ||
| 20. |  | M. G. Ruppert Self-sensing, estimation and control in multifrequency Atomic Force Microscopy. (Journal Article) Journal & Proceedings of the Royal Society of New South Wales, 151 (1), pp. 111, 2018, ISSN: 0035-9173/18/010111-01. (Abstract | Links | BibTeX | Tags: Cantilever, MEMS, Multifrequency AFM, Sensors, Smart Structures, SPM, System Identification, Vibration Control) @article{Ruppert2018b, title = {Self-sensing, estimation and control in multifrequency Atomic Force Microscopy. }, author = {M. G. Ruppert}, url = {https://royalsoc.org.au/images/pdf/journal/151-1-Ruppert.pdf}, issn = {0035-9173/18/010111-01}, year = {2018}, date = {2018-06-01}, journal = {Journal & Proceedings of the Royal Society of New South Wales}, volume = {151}, number = {1}, pages = {111}, abstract = {Despite the undeniable success of the atomic force microscope (AFM), dynamic techniques still face limitations in terms of spatial resolution, imaging speed and high cost of acquisition. In order to expand the capabilities of the instrument, it was realized that the information about the nano-mechanical properties of a sample are encoded over a range of frequencies and the excitation and detection of higher-order eigenmodes of the micro-cantilever open up further informa- tion channels. The ability to control these modes and their fast responses to excitation is believed to be the key to unravelling the true potential of these ethods. This work addresses three major drawbacks of the standard AFM setup, which limit the feasibility of multi-frequency approaches. First, microelectromechanical system (MEMS) probes with integrated piezoelectric layers is motivated, enabling the development of novel multimode self-sensing and self-actuating techniques. Specifically, these piezoelectric transduction schemes permit the miniaturization of the entire AFM towards a cost-effective single-chip device with nanoscale precision in a much smaller form factor than that of conventional macroscale instruments. Second, the integrated actuation enables the development of multimode controllers which exhibits remarkable performance in arbitrarily modifying the quality factor of multiple eigenmodes and comes with inherent stability robustness. The experimental results demonstrate improved imaging stability, higher scan speeds and adjustable contrast when mapping nano-mechanical properties of soft samples. Last, in light of the demand for constantly increasing imaging speeds while providing multi-frequency flexibility, the estimation of multiple components of the high-frequency deflection signal is performed with a linear time-varying multi-frequency Kalman filter. The chosen representation allows for an efficient high-bandwidth implementation on a Field Programmable Gate Array. Tracking bandwidth, noise performance and trimodal AFM imaging on a two-component polymer sample are verified and shown to be superior to that of the commonly used lock-in amplifier.}, keywords = {Cantilever, MEMS, Multifrequency AFM, Sensors, Smart Structures, SPM, System Identification, Vibration Control}, pubstate = {published}, tppubtype = {article} } Despite the undeniable success of the atomic force microscope (AFM), dynamic techniques still face limitations in terms of spatial resolution, imaging speed and high cost of acquisition. In order to expand the capabilities of the instrument, it was realized that the information about the nano-mechanical properties of a sample are encoded over a range of frequencies and the excitation and detection of higher-order eigenmodes of the micro-cantilever open up further informa- tion channels. The ability to control these modes and their fast responses to excitation is believed to be the key to unravelling the true potential of these ethods. This work addresses three major drawbacks of the standard AFM setup, which limit the feasibility of multi-frequency approaches. First, microelectromechanical system (MEMS) probes with integrated piezoelectric layers is motivated, enabling the development of novel multimode self-sensing and self-actuating techniques. Specifically, these piezoelectric transduction schemes permit the miniaturization of the entire AFM towards a cost-effective single-chip device with nanoscale precision in a much smaller form factor than that of conventional macroscale instruments. Second, the integrated actuation enables the development of multimode controllers which exhibits remarkable performance in arbitrarily modifying the quality factor of multiple eigenmodes and comes with inherent stability robustness. The experimental results demonstrate improved imaging stability, higher scan speeds and adjustable contrast when mapping nano-mechanical properties of soft samples. Last, in light of the demand for constantly increasing imaging speeds while providing multi-frequency flexibility, the estimation of multiple components of the high-frequency deflection signal is performed with a linear time-varying multi-frequency Kalman filter. The chosen representation allows for an efficient high-bandwidth implementation on a Field Programmable Gate Array. Tracking bandwidth, noise performance and trimodal AFM imaging on a two-component polymer sample are verified and shown to be superior to that of the commonly used lock-in amplifier. |
| 19. |  | M. G. Ruppert, S. I. Moore, M. Zawierta, G. Putrino, Y. K. Yong Advanced Sensing and Control with Active Cantilevers for Multimodal Atomic Force Microscopy (Conference) 7th Multifrequency AFM Conference, Madrid, Spain, 2018. (Abstract | BibTeX | Tags: AFM, Cantilever, MEMS, Multifrequency AFM, Sensors, Smart Structures, SPM, Vibration Control) @conference{Ruppert2018, title = {Advanced Sensing and Control with Active Cantilevers for Multimodal Atomic Force Microscopy}, author = {M. G. Ruppert and S. I. Moore and M. Zawierta and G. Putrino and Y. K. Yong}, year = {2018}, date = {2018-04-18}, booktitle = {7th Multifrequency AFM Conference}, address = {Madrid, Spain}, abstract = {Atomic force microscopy (AFM) cantilevers with integrated actuation and sensing on the chip level 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 interferences. 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. Consequently, conventional cantilever instrumentation requires external piezo acoustic excitation as well as an external optical deflection sensor. Both of these components are not optimal for current trends in multifrequency AFM technology which revolve around further down-sizing, parallelization and measurements at multiple higher eigenmodes. Using microelectromechanical systems (MEMS) fabrication processes, this work aims to optimize cantilever instrumentation by realizing a new class of probes with high-performance integrated actuators and sensors. Equipped with multiple integrated piezoelectric layers for both actuation and sensing, these cantilevers are capable of achieving an increased higher eigenmode sensitivity and/or guaranteed collocated system properties compared to commercially available counterparts; examples of such designs are shown in Figure 1. The geometry as well as the integrated actuator/sensor arrangement is optimized using finite element modelling with individual design goals. The designs are realized using a commercial MEMS fabrication process and only require a simple five-mask patterning and etching process and post-fabricated sharp tips.}, keywords = {AFM, Cantilever, MEMS, Multifrequency AFM, Sensors, Smart Structures, SPM, Vibration Control}, pubstate = {published}, tppubtype = {conference} } Atomic force microscopy (AFM) cantilevers with integrated actuation and sensing on the chip level 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 interferences. 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. Consequently, conventional cantilever instrumentation requires external piezo acoustic excitation as well as an external optical deflection sensor. Both of these components are not optimal for current trends in multifrequency AFM technology which revolve around further down-sizing, parallelization and measurements at multiple higher eigenmodes. Using microelectromechanical systems (MEMS) fabrication processes, this work aims to optimize cantilever instrumentation by realizing a new class of probes with high-performance integrated actuators and sensors. Equipped with multiple integrated piezoelectric layers for both actuation and sensing, these cantilevers are capable of achieving an increased higher eigenmode sensitivity and/or guaranteed collocated system properties compared to commercially available counterparts; examples of such designs are shown in Figure 1. The geometry as well as the integrated actuator/sensor arrangement is optimized using finite element modelling with individual design goals. The designs are realized using a commercial MEMS fabrication process and only require a simple five-mask patterning and etching process and post-fabricated sharp tips. |
2017 | ||
| 18. |  | M. G. Ruppert, Y. K. Yong Note: Guaranteed collocated multimode control of an atomic force microscope cantilever using on-chip piezoelectric actuation and sensing (Journal Article) Review of Scientific Instruments, 88 (086109), 2017. (Abstract | Links | BibTeX | Tags: AFM, Cantilever, MEMS, Multifrequency AFM, Piezoelectric Transducers and Drives, System Identification, Vibration Control) @article{Ruppert2017b, title = {Note: Guaranteed collocated multimode control of an atomic force microscope cantilever using on-chip piezoelectric actuation and sensing}, author = {M. G. Ruppert and Y. K. Yong}, url = {http://www.precisionmechatronicslab.com/wp-content/uploads/2017/08/2017_JNote_RSI_Vol88_086109-2.pdf}, doi = {10.1063/1.4990451}, year = {2017}, date = {2017-08-15}, journal = {Review of Scientific Instruments}, volume = {88}, number = {086109}, abstract = {The quality (Q) factor is an important parameter of the resonance of the microcantilever as it determines both imaging bandwidth and force sensitivity. The ability to control the Q factor of multiple modes is believed to be of great benefit for atomic force microscopy techniques involving multiple eigenmodes. In this paper, we propose a novel cantilever design employing multiple piezoelectric transducers which are used for separated actuation and sensing, leading to guaranteed collocation of the first eight eigenmodes up to 3 MHz. The design minimizes the feedthrough usually observed with these systems by incorporating a guard trace on the cantilever chip. As a result, a multimode Q controller is demonstrated to be able to modify the quality factor of the first two eigenmodes over up to four orders of magnitude without sacrificing robust stability.}, keywords = {AFM, Cantilever, MEMS, Multifrequency AFM, Piezoelectric Transducers and Drives, System Identification, Vibration Control}, pubstate = {published}, tppubtype = {article} } The quality (Q) factor is an important parameter of the resonance of the microcantilever as it determines both imaging bandwidth and force sensitivity. The ability to control the Q factor of multiple modes is believed to be of great benefit for atomic force microscopy techniques involving multiple eigenmodes. In this paper, we propose a novel cantilever design employing multiple piezoelectric transducers which are used for separated actuation and sensing, leading to guaranteed collocation of the first eight eigenmodes up to 3 MHz. The design minimizes the feedthrough usually observed with these systems by incorporating a guard trace on the cantilever chip. As a result, a multimode Q controller is demonstrated to be able to modify the quality factor of the first two eigenmodes over up to four orders of magnitude without sacrificing robust stability. |
| 17. |  | M. G. Ruppert, M. Maroufi, A. Bazaei, S. O. R. Moheimani Kalman Filter Enabled High-Speed Control of a MEMS Nanopositioner (Inproceeding) 20th IFAC World Congress, pp. 15554-15560, 2017. (Abstract | BibTeX | Tags: MEMS, Nanopositioning, Tracking Control, Vibration Control) @inproceedings{Ruppert2017b, title = {Kalman Filter Enabled High-Speed Control of a MEMS Nanopositioner}, author = {M. G. Ruppert and M. Maroufi and A. Bazaei and S. O. R. Moheimani}, year = {2017}, date = {2017-07-01}, booktitle = {20th IFAC World Congress}, volume = {50}, number = {1}, pages = {15554-15560}, abstract = {We demonstrate a novel tracking controller formulation based on a linear time-varying Kalman Filter to regulate amplitude and phase of a reference signal independently. The method is applicable to sinusoidal references such as spiral, cycloid and Lissajous trajectories which are commonly used for imaging in high-speed Atomic Force Microscopy (AFM). A Microelectromechanical Systems (MEMS) based nanopositioner, whose fundamental resonance frequency is dampened with an additional damping feedback loop, is employed. For a scan range of 2um, we demonstrate experimental tracking of sinusoids with frequencies as high as 5kHz, well beyond the open-loop fundamental resonance, with a tracking error of only 4.6nm.}, keywords = {MEMS, Nanopositioning, Tracking Control, Vibration Control}, pubstate = {published}, tppubtype = {inproceedings} } We demonstrate a novel tracking controller formulation based on a linear time-varying Kalman Filter to regulate amplitude and phase of a reference signal independently. The method is applicable to sinusoidal references such as spiral, cycloid and Lissajous trajectories which are commonly used for imaging in high-speed Atomic Force Microscopy (AFM). A Microelectromechanical Systems (MEMS) based nanopositioner, whose fundamental resonance frequency is dampened with an additional damping feedback loop, is employed. For a scan range of 2um, we demonstrate experimental tracking of sinusoids with frequencies as high as 5kHz, well beyond the open-loop fundamental resonance, with a tracking error of only 4.6nm. |
2016 | ||
| 16. |  | M. G. Ruppert, S. O. R. Moheimani Multimode Q Control in Tapping-Mode AFM: Enabling Imaging on Higher Flexural Eigenmodes (Journal Article) IEEE Transactions on Control Systems Technology, 24 (4), pp. 1149-1159, 2016. (Abstract | Links | BibTeX | Tags: MEMS, Multifrequency AFM, SPM, System Identification, Vibration Control) @article{Ruppert2016b, title = {Multimode Q Control in Tapping-Mode AFM: Enabling Imaging on Higher Flexural Eigenmodes}, author = {M. G. Ruppert and S. O. R. Moheimani}, doi = {10.1109/TCST.2015.2478077}, year = {2016}, date = {2016-07-01}, journal = {IEEE Transactions on Control Systems Technology}, volume = {24}, number = {4}, pages = {1149-1159}, abstract = {Numerous dynamic Atomic Force Microscopy (AFM) methods have appeared in recent years, which make use of the excitation and detection of higher order eigenmodes of the microcantilever. The ability to control these modes and their responses to excitation is believed to be the key to unraveling the true potential of these methods. In this work, we highlight a multi-mode Q control method that exhibits remarkable damping performance and stability robustness. The experimental results obtained in ambient conditions demonstrate improved imaging stability by damping non-driven resonant modes when scanning is performed at a higher eigenmode of the cantilever. Higher scan speeds are shown to result from a decrease in transient response time. }, keywords = {MEMS, Multifrequency AFM, SPM, System Identification, Vibration Control}, pubstate = {published}, tppubtype = {article} } Numerous dynamic Atomic Force Microscopy (AFM) methods have appeared in recent years, which make use of the excitation and detection of higher order eigenmodes of the microcantilever. The ability to control these modes and their responses to excitation is believed to be the key to unraveling the true potential of these methods. In this work, we highlight a multi-mode Q control method that exhibits remarkable damping performance and stability robustness. The experimental results obtained in ambient conditions demonstrate improved imaging stability by damping non-driven resonant modes when scanning is performed at a higher eigenmode of the cantilever. Higher scan speeds are shown to result from a decrease in transient response time. |
| 15. |  | M. G. Ruppert, S. O. R. Moheimani High-bandwidth Multimode Self-sensing in Bimodal Atomic Force Microscopy (Journal Article) Beilstein Journal of Nanotechnology, 7 , pp. 284-295, 2016. (Abstract | Links | BibTeX | Tags: MEMS, Multifrequency AFM, Piezoelectric Transducers and Drives, Vibration Control) @article{Ruppert2016b, title = {High-bandwidth Multimode Self-sensing in Bimodal Atomic Force Microscopy}, author = {M. G. Ruppert and S. O. R. Moheimani}, doi = {10.3762/bjnano.7.26}, year = {2016}, date = {2016-02-24}, journal = {Beilstein Journal of Nanotechnology}, volume = {7}, pages = {284-295}, abstract = {Using standard microelectromechanical system (MEMS) processes to coat a microcantilever with a piezoelectric layer results in a versatile transducer with inherent self-sensing capabilities. For applications in multifrequency atomic force microscopy (MF-AFM), we illustrate that a single piezoelectric layer can be simultaneously used for multimode excitation and detection of the cantilever deflection. This is achieved by a charge sensor with a bandwidth of 10 MHz and dual feedthrough cancellation to recover the resonant modes that are heavily buried in feedthrough originating from the piezoelectric capacitance. The setup enables the omission of the commonly used piezoelectric stack actuator and optical beam deflection sensor, alleviating limitations due to distorted frequency responses and instrumentation cost, respectively. The proposed method benefits from a more than two orders of magnitude increase in deflection to strain sensitivity on the fifth eigenmode leading to a remarkable signal-to-noise ratio. Experimental results using bimodal AFM imaging on a two component polymer sample validate that the self-sensing scheme can therefore be used to provide both the feedback signal, for topography imaging on the fundamental mode, and phase imaging on the higher eigenmode.}, keywords = {MEMS, Multifrequency AFM, Piezoelectric Transducers and Drives, Vibration Control}, pubstate = {published}, tppubtype = {article} } Using standard microelectromechanical system (MEMS) processes to coat a microcantilever with a piezoelectric layer results in a versatile transducer with inherent self-sensing capabilities. For applications in multifrequency atomic force microscopy (MF-AFM), we illustrate that a single piezoelectric layer can be simultaneously used for multimode excitation and detection of the cantilever deflection. This is achieved by a charge sensor with a bandwidth of 10 MHz and dual feedthrough cancellation to recover the resonant modes that are heavily buried in feedthrough originating from the piezoelectric capacitance. The setup enables the omission of the commonly used piezoelectric stack actuator and optical beam deflection sensor, alleviating limitations due to distorted frequency responses and instrumentation cost, respectively. The proposed method benefits from a more than two orders of magnitude increase in deflection to strain sensitivity on the fifth eigenmode leading to a remarkable signal-to-noise ratio. Experimental results using bimodal AFM imaging on a two component polymer sample validate that the self-sensing scheme can therefore be used to provide both the feedback signal, for topography imaging on the fundamental mode, and phase imaging on the higher eigenmode. |
| 14. |  | M. G. Ruppert, K. S. Karvinen, S. L. Wiggins, S. O. R. Moheimani A Kalman Filter for Amplitude Estimation in High-Speed Dynamic Mode Atomic Force Microscopy (Journal Article) IEEE Transactions on Control Systems Technology, 24 (1), pp. 276-284, 2016. (Abstract | Links | BibTeX | Tags: Multifrequency AFM, SPM, Vibration Control) @article{Ruppert2016b, title = {A Kalman Filter for Amplitude Estimation in High-Speed Dynamic Mode Atomic Force Microscopy}, author = {M. G. Ruppert and K. S. Karvinen and S. L. Wiggins and S. O. R. Moheimani}, doi = {10.1109/TCST.2015.2435654}, year = {2016}, date = {2016-01-01}, journal = {IEEE Transactions on Control Systems Technology}, volume = {24}, number = {1}, pages = {276-284}, abstract = {A fundamental challenge in dynamic mode atomic force microscopy (AFM) is the estimation of the cantilever oscillation amplitude from the deflection signal which might be distorted by noise and/or high-frequency components. When the cantilever is excited at resonance, its deflection is typically obtained via narrowband demodulation using a lock-in amplifier. However, the bandwidth of this measurement technique is ultimately bounded by the low-pass filter which must be employed after demodulation to attenuate the component at twice the carrier frequency. Furthermore, to measure the amplitude of multiple frequency components such as higher eigenmodes and/or higher harmonics in multifrequency AFM, multiple lock-in amplifiers must be employed. In this work, the authors propose the estimation of amplitude and phase using a linear time-varying Kalman filter which is easily extended to multiple frequencies. Experimental results are obtained using square-modulated sine waves and closed-loop AFM scans, verifying the performance of the proposed Kalman filter.}, keywords = {Multifrequency AFM, SPM, Vibration Control}, pubstate = {published}, tppubtype = {article} } A fundamental challenge in dynamic mode atomic force microscopy (AFM) is the estimation of the cantilever oscillation amplitude from the deflection signal which might be distorted by noise and/or high-frequency components. When the cantilever is excited at resonance, its deflection is typically obtained via narrowband demodulation using a lock-in amplifier. However, the bandwidth of this measurement technique is ultimately bounded by the low-pass filter which must be employed after demodulation to attenuate the component at twice the carrier frequency. Furthermore, to measure the amplitude of multiple frequency components such as higher eigenmodes and/or higher harmonics in multifrequency AFM, multiple lock-in amplifiers must be employed. In this work, the authors propose the estimation of amplitude and phase using a linear time-varying Kalman filter which is easily extended to multiple frequencies. Experimental results are obtained using square-modulated sine waves and closed-loop AFM scans, verifying the performance of the proposed Kalman filter. |
2015 | ||
| 13. |  | M. G. Ruppert, S. O. R. Moheimani Multi-Mode Q Control in Multifrequency Atomic Force Microscopy (Inproceeding) ASME International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, pp. V004T09A009, Boston, Massachusetts, USA, 2015. (Abstract | Links | BibTeX | Tags: MEMS, Multifrequency AFM, SPM, Vibration Control) @inproceedings{Ruppert2015, title = {Multi-Mode Q Control in Multifrequency Atomic Force Microscopy}, author = {M. G. Ruppert and S. O. R. Moheimani}, doi = {10.1115/DETC2015-46989}, year = {2015}, date = {2015-08-01}, booktitle = {ASME International Design Engineering Technical Conferences & Computers and Information in Engineering Conference}, pages = {V004T09A009}, address = {Boston, Massachusetts, USA}, abstract = {Various Atomic Force Microscopy (AFM) modes have emerged which rely on the excitation and detection of multiple eigenmodes of the microcantilever. The conventional control loops employed in multifrequency AFM (MF-AFM) such as bimodal imaging where the fundamental mode is used to map the topography and a higher eigenmode is used to map sample material properties only focus on maintaining low bandwidth signals such as amplitude and/ or frequency shift. However, the ability to perform additional high bandwidth control of the quality (Q) factor of the participating modes is believed to be imperative to unfolding the full potential of these methods. This can be achieved by employing a multi-mode Q control approach utilizing positive position feedback. The controller exhibits remarkable performance in arbitrarily modifying the Q factor of multiple eigenmodes as well as guaranteed stability properties when used on flexible structures with collocated actuators and sensors. A controller design method based on pole placement optimization is proposed for setting an arbitrary on-resonance Q factor of the participating eigenmodes. Experimental results using bimodal AFM imaging on a two component polymer sample are presented.}, keywords = {MEMS, Multifrequency AFM, SPM, Vibration Control}, pubstate = {published}, tppubtype = {inproceedings} } Various Atomic Force Microscopy (AFM) modes have emerged which rely on the excitation and detection of multiple eigenmodes of the microcantilever. The conventional control loops employed in multifrequency AFM (MF-AFM) such as bimodal imaging where the fundamental mode is used to map the topography and a higher eigenmode is used to map sample material properties only focus on maintaining low bandwidth signals such as amplitude and/ or frequency shift. However, the ability to perform additional high bandwidth control of the quality (Q) factor of the participating modes is believed to be imperative to unfolding the full potential of these methods. This can be achieved by employing a multi-mode Q control approach utilizing positive position feedback. The controller exhibits remarkable performance in arbitrarily modifying the Q factor of multiple eigenmodes as well as guaranteed stability properties when used on flexible structures with collocated actuators and sensors. A controller design method based on pole placement optimization is proposed for setting an arbitrary on-resonance Q factor of the participating eigenmodes. Experimental results using bimodal AFM imaging on a two component polymer sample are presented. |
2013 | ||
| 12. |  | M. G. Ruppert, M. Fairbairn, S. O. R. Moheimani Multi-Mode Resonant Control of a Microcantilever for Atomic Force Microscopy (Inproceeding) IEEE/ASME International Conference on Advanced Intelligent Mechatronics, pp. 77-82, Wollongong, Australia, 2013. (Abstract | Links | BibTeX | Tags: MEMS, Multifrequency AFM, Vibration Control) @inproceedings{Ruppert2013, title = {Multi-Mode Resonant Control of a Microcantilever for Atomic Force Microscopy}, author = {M. G. Ruppert and M. Fairbairn and S. O. R. Moheimani}, doi = {10.1109/AIM.2013.6584071}, year = {2013}, date = {2013-07-09}, booktitle = {IEEE/ASME International Conference on Advanced Intelligent Mechatronics}, pages = {77-82}, address = {Wollongong, Australia}, abstract = {When operating the Atomic Force Microscope in tapping mode it is possible to decrease the quality factor of the microcantilever to enhance scan speed. %Standard Q Control techniques involve velocity feedback with the disadvantage of additional sensor equipment, or time-delay position feedback which may lead to instabilities of out-of-bandwidth modes.Various resonance controllers have been proposed which do not rely on expensive velocity sensors and guarantee stability of the closed loop system even in the presence of unmodeled dynamics. A new field of Atomic Force Microscopy is evolving, which makes use of multiple frequency excitation and detection of the cantilever modes making it necessary to be able to control these modes and their response to excitation. This work proposes a multi-mode Q control approach utilizing positive position feedback, offering full control over the first two flexural modes of the cantilever. By completely damping the first mode and adjusting the quality factor of the second mode, it is possible to scan and obtain images at the second resonance frequency which improves image quality at high scan speeds due to the increased bandwidth of the z-axis feedback loop.}, keywords = {MEMS, Multifrequency AFM, Vibration Control}, pubstate = {published}, tppubtype = {inproceedings} } When operating the Atomic Force Microscope in tapping mode it is possible to decrease the quality factor of the microcantilever to enhance scan speed. %Standard Q Control techniques involve velocity feedback with the disadvantage of additional sensor equipment, or time-delay position feedback which may lead to instabilities of out-of-bandwidth modes.Various resonance controllers have been proposed which do not rely on expensive velocity sensors and guarantee stability of the closed loop system even in the presence of unmodeled dynamics. A new field of Atomic Force Microscopy is evolving, which makes use of multiple frequency excitation and detection of the cantilever modes making it necessary to be able to control these modes and their response to excitation. This work proposes a multi-mode Q control approach utilizing positive position feedback, offering full control over the first two flexural modes of the cantilever. By completely damping the first mode and adjusting the quality factor of the second mode, it is possible to scan and obtain images at the second resonance frequency which improves image quality at high scan speeds due to the increased bandwidth of the z-axis feedback loop. |
2009 | ||
| 11. | Y. K. Yong, S. O. R. Moheimani Vibration control of a novel tube scanner using piezoelectric strain-induced voltage (Inproceeding) Proc. IEEE/ASME International Conference on Advanced Intelligent Mechatronics , 2009. (Links | BibTeX | Tags: Nanopositioning, Sensors, Vibration Control) @inproceedings{Yong20091070, title = {Vibration control of a novel tube scanner using piezoelectric strain-induced voltage}, author = {Y. K. Yong and S. O. R. Moheimani}, doi = {10.1109/AIM.2009.5229728}, year = {2009}, date = {2009-07-01}, booktitle = {Proc. IEEE/ASME International Conference on Advanced Intelligent Mechatronics }, journal = {IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM}, keywords = {Nanopositioning, Sensors, Vibration Control}, pubstate = {published}, tppubtype = {inproceedings} } |
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2006 | ||
| 10. | D. Niederberger, S. Behrens, A. J. Fleming, S. O. R. Moheimani, M. Morari Adaptive electromagnetic shunt damping (Journal Article) IEEE/ASME Transactions on Mechatronics, 11 (1), pp. 103–108, 2006. (Links | BibTeX | Tags: Vibration Control) @article{J06c, title = {Adaptive electromagnetic shunt damping}, author = {D. Niederberger and S. Behrens and A. J. Fleming and S. O. R. Moheimani and M. Morari}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/J06c.pdf}, year = {2006}, date = {2006-12-01}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {11}, number = {1}, pages = {103--108}, keywords = {Vibration Control}, pubstate = {published}, tppubtype = {article} } |
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| 9. | A. J. Fleming, S. Behrens, S. O. R. Moheimani Inertial vibration control using a shunted electromagnetic transducer (Journal Article) IEEE/ASME Transactions on Mechatronics, 11 (1), pp. 84–92, 2006. (Links | BibTeX | Tags: Vibration Control) @article{J06a, title = {Inertial vibration control using a shunted electromagnetic transducer}, author = {A. J. Fleming and S. Behrens and S. O. R. Moheimani}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/J06a.pdf}, year = {2006}, date = {2006-12-01}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {11}, number = {1}, pages = {84--92}, keywords = {Vibration Control}, pubstate = {published}, tppubtype = {article} } |
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2005 | ||
| 8. | S. Behrens, A. J. Fleming, S. O. R. Moheimani Passive vibration control via electromagnetic shunt damping (Journal Article) IEEE/ASME Transactions on Mechatronics, 10 (1), pp. 118–122, 2005. (Links | BibTeX | Tags: Vibration Control) @article{J05b, title = {Passive vibration control via electromagnetic shunt damping}, author = {S. Behrens and A. J. Fleming and S. O. R. Moheimani}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/J05b.pdf}, year = {2005}, date = {2005-12-01}, journal = {IEEE/ASME Transactions on Mechatronics}, volume = {10}, number = {1}, pages = {118--122}, keywords = {Vibration Control}, pubstate = {published}, tppubtype = {article} } |
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| 7. | A. J. Fleming, S. Behrens, S. O. R. Moheimani Synthesis and implementation of sensor-less active shunt controllers for electromagnetically actuated systems (Journal Article) IEEE Transactions on Control Systems Technology, 13 (2), pp. 246–261, 2005. (Links | BibTeX | Tags: Vibration Control) @article{J05a, title = {Synthesis and implementation of sensor-less active shunt controllers for electromagnetically actuated systems}, author = {A. J. Fleming and S. Behrens and S. O. R. Moheimani}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/J05a.pdf}, year = {2005}, date = {2005-12-01}, journal = {IEEE Transactions on Control Systems Technology}, volume = {13}, number = {2}, pages = {246--261}, keywords = {Vibration Control}, pubstate = {published}, tppubtype = {article} } |
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| 6. | A. J. Fleming, S. O. R. Moheimani Proof-mass inertial vibration control using a shunted electromagnetic transducer (Inproceeding) Proc. IFAC World Congress, Prague, Czech Republic, 2005. (Links | BibTeX | Tags: Vibration Control) @inproceedings{C05a, title = {Proof-mass inertial vibration control using a shunted electromagnetic transducer}, author = {A. J. Fleming and S. O. R. Moheimani}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/C05a.pdf}, year = {2005}, date = {2005-01-01}, booktitle = {Proc. IFAC World Congress}, address = {Prague, Czech Republic}, keywords = {Vibration Control}, pubstate = {published}, tppubtype = {inproceedings} } |
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2004 | ||
| 5. | S. Behrens, A. J. Fleming, S. O. R. Moheimani Control orientated synthesis of electromagnetic shunt impedances for vibration isolation (Inproceeding) Proc. IFAC Symposium on Mechatronic Systems, Sydney, Australia, 2004. (Links | BibTeX | Tags: Vibration Control) @inproceedings{C04d, title = {Control orientated synthesis of electromagnetic shunt impedances for vibration isolation}, author = {S. Behrens and A. J. Fleming and S. O. R. Moheimani}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/C04d.pdf}, year = {2004}, date = {2004-01-01}, booktitle = {Proc. IFAC Symposium on Mechatronic Systems}, address = {Sydney, Australia}, keywords = {Vibration Control}, pubstate = {published}, tppubtype = {inproceedings} } |
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| 4. | S. Behrens, A. J. Fleming, S. O. R. Moheimani Vibration isolation using a shunted electromagnetic transducer (Inproceeding) Proc. SPIE Symposium on Smart Structures & Materials -- Damping and Isolation, San Diego, CA, 2004. (Links | BibTeX | Tags: Vibration Control) @inproceedings{D04a, title = {Vibration isolation using a shunted electromagnetic transducer}, author = {S. Behrens and A. J. Fleming and S. O. R. Moheimani}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/D04a.pdf}, year = {2004}, date = {2004-01-01}, booktitle = {Proc. SPIE Symposium on Smart Structures & Materials -- Damping and Isolation}, address = {San Diego, CA}, keywords = {Vibration Control}, pubstate = {published}, tppubtype = {inproceedings} } |
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2003 | ||
| 3. | A. J. Fleming, S. O. R. Moheimani Active H₂ and H[subscript infinity] shunt control of electromagnetic transducers (Inproceeding) Proc. IEEE Conference on Decision and Control, Maui, HI, 2003. (Links | BibTeX | Tags: Vibration Control) @inproceedings{C03a, title = {Active H₂ and H[subscript infinity] shunt control of electromagnetic transducers}, author = {A. J. Fleming and S. O. R. Moheimani}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/C03a.pdf}, year = {2003}, date = {2003-01-01}, booktitle = {Proc. IEEE Conference on Decision and Control}, address = {Maui, HI}, keywords = {Vibration Control}, pubstate = {published}, tppubtype = {inproceedings} } |
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| 2. | S. Behrens, A. J. Fleming, S. O. R. Moheimani Electrodynamic vibration suppression (Inproceeding) Proc. SPIE Symposium on Smart Structures & Materials -- Damping and Isolation, San Diego, CA, 2003. (Links | BibTeX | Tags: Vibration Control) @inproceedings{D03d, title = {Electrodynamic vibration suppression}, author = {S. Behrens and A. J. Fleming and S. O. R. Moheimani}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/D03d.pdf}, year = {2003}, date = {2003-01-01}, booktitle = {Proc. SPIE Symposium on Smart Structures & Materials -- Damping and Isolation}, address = {San Diego, CA}, keywords = {Vibration Control}, pubstate = {published}, tppubtype = {inproceedings} } |
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| 1. | S. Behrens, A. J. Fleming, S. O. R. Moheimani Electromagnetic shunt damping (Inproceeding) Proc. IEEE/ASME Confernece on Advanced Intelligent Mechatronics, Kobe, Japan, 2003. (Links | BibTeX | Tags: Vibration Control) @inproceedings{C03b, title = {Electromagnetic shunt damping}, author = {S. Behrens and A. J. Fleming and S. O. R. Moheimani}, url = {http://www.precisionmechatronicslab.com/wp-content/publications/C03b.pdf}, year = {2003}, date = {2003-01-01}, booktitle = {Proc. IEEE/ASME Confernece on Advanced Intelligent Mechatronics}, address = {Kobe, Japan}, keywords = {Vibration Control}, pubstate = {published}, tppubtype = {inproceedings} } |
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