| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2015: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
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| Outline of Final Research Achievements |
For the high-power ultrasonic transducers operation, it is often required to control the resonant frequency to realize non-sinusoidal wave. For example, ultrasonic motors which are driven with saw-shaped vibration, the shift of resonant frequency results in the performance degradation. To overcome this problem, this study proposes a dynamic control system of the resonant frequency modification by connecting MOSFETs to the additional piezoelectric parts. By switching on and off of the MOSFETs, the electric boundary condition for the additional piezoelectric parts changes between shorten and open. Generally, the resonant frequencies under these condition have the relationship of f(shorten) < f(open) because of the piezoelectric effect. By switching the MOSFETs as the same frequency to the driving frequency and changing the switching duty ratio, the resonant frequency could be modified as a function of the duty ratio.
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