Mansour,; Seethaler,; Teo,; Yong,; Fleming, (2017): Piezoelectric Bimorph Actuator with Integrated Strain Sensing Electrodes. In: IEEE Sensors, Glasgow, Scotland, 2017. (Type: Inproceeding | Abstract | Links | BibTeX)@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. |
Eielsen,; Fleming, (2017): Existing Methods for Improving the Accuracy of Digital-to-Analog Converters. In: Review of Scientific Instruments, Accepted , 2017. (Type: Journal Article | Abstract | Links | BibTeX)@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},
year = {2017},
date = {2017-10-01},
journal = {Review of Scientific Instruments},
volume = {Accepted},
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. |
Ruppert,; Harcombe,; Ragazzon,; Moheimani,; Fleming, (2017): A Review of Demodulation Techniques for Amplitude Modulation Atomic Force Microscopy. In: Bellstein Journal of Nanotechnology, In Press , 2017. (Type: Journal Article | Abstract | Links | BibTeX)@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/2017/07/m11627988-1.pdf},
year = {2017},
date = {2017-09-01},
journal = {Bellstein Journal of Nanotechnology},
volume = {In Press},
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. |
Islam,; Fleming, (2017): An Algorithm for Transmitter Optimization in Electromagnetic Tracking Systems. In: IEEE Transactions on Magnetics, Accepted , 2017. (Type: Journal Article | Links | BibTeX)@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},
year = {2017},
date = {2017-08-30},
journal = {IEEE Transactions on Magnetics},
volume = {Accepted},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
Ruppert,; Yong, (2017): Note: Guaranteed collocated multimode control of an atomic force microscope cantilever using on-chip piezoelectric actuation and sensing. In: Review of Scientific Instruments, 88 (086109), 2017. (Type: Journal Article | Abstract | Links | BibTeX)@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 = {},
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. |
Yong,; Fleming, (2017): An Improved Low-frequency Correction Technique for Piezoelectric Force Sensors in High-speed Nanopositioning Systems. In: Review of Scientific Instruments, 88 (046105), pp. 1-3, 2017. (Type: Journal Article | Abstract | Links | BibTeX)@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 |
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