Dynamic Control of the Piezoelectric Transducer’s Resonant Frequency using MOSFET Switching
H. Yokozawa1, J. Twiefel 2, M. Weinstein 2 and T. Morita1
1 The University of Tokyo, Tokyo, Japan
2 Leibniz Universität Hannover, Hannover, Germany
For driving ultrasonic motors, it is often required to control the resonant frequency of a transducer between some mode shapes or numbers; for example, some of them are driven with combined vibration of longitudinal and bending modes, and the shift of the resonant frequency degrades their performance. As the source of this shift, the boundary condition’s change and the nonlinear effect during the high power driving should be taken into account. To overcome this problem, this study proposes a dynamic control system of the resonant frequency modification by connecting FETs to the additional piezoelectric parts differently from the driving piezoelectric part. By switching on and off the FETs, the electric boundary condition for the additional piezoelectric parts changes between shorten and open conditions. Generally, the resonant frequencies under these conditions have the relationship of fshorten _ fopen because of the piezoelectric effect. By switching the FETs with the same frequency as the driving frequency, the resonant frequency could be modified as a function of the duty ratio.
ACTUATOR 2016 Manuscript A1.10
Publication date: 01/06/2016
Manuscript A1.10 published in Conference Proceedings ACTUATOR 2016
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