Omidbeike, M; Yong, Y K; Fleming, A J Sensing and Decentralized Control of a Five-Axis Monolithic Nanopositioning Stage Inproceedings In: IFAC World Congress, 2020. Abstract | BibTeX @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. },
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pubstate = {published},
tppubtype = {inproceedings}
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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. |
Xavier, M S; Fleming, A J; Yong, Y K Modelling and Simulation of Pneumatic Sources for Soft Robotic Applications Inproceedings In: IEEE/ASME International Conference on Advanced Intelligent Mechatronics, Boston, MA, 2020. Abstract | Links | BibTeX @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.},
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pubstate = {published},
tppubtype = {inproceedings}
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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. |
Raghunvanshi, D S; Moore, S I; Fleming, A J; Yong, Y K Electrode Configurations for Piezoelectric Tube Actuators With Improved Scan Range and Reduced Cross-Coupling Journal Article In: IEEE/ASME Transactions on Mechatronics, 25 (3), pp. 1479-1486, 2020, ISSN: 00346748. Abstract | Links | BibTeX @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. |
Ruppert, M G; Bartlett, N J; Yong, Y K; Fleming, A J Amplitude Noise Spectrum of a Lock-in Amplifier: Application to Microcantilever Noise Measurements Journal Article In: Sensors and Actuators A: Physical, 312 , pp. 112092, 2020. Abstract | Links | BibTeX @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}
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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. |
Eielsen, A A; Leth, J; Fleming, A J; Wills, A G; Ninness, B Large-amplitude Dithering Mitigates Glitches in Digital-to-analogue Converters Journal Article In: IEEE Transactions on Signal Processing, 68 , pp. 1950-1963, 2020, ISSN: 19410476. Abstract | Links | BibTeX @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. |
