Projects

@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 = {https://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}

}

@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 = {},

pubstate = {published},

tppubtype = {article}

}

@article{J15f,

title = {A Closed-Loop Phase-Locked Interferometer for Wide Bandwidth Position Sensing},

author = {A. J. Fleming and B. S. Routley},

url = {https://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}

}