Analysis of driving mechanism for tiny piezoelectric linear motor

Recently, a tiny piezoelectric linear motor using a vibration mode of the transducer has been invented. The motor consists of a shaft, mobile element, and piezoelectric transducer using a piezoelectric radial mode bimorph disk. The fringe of the bimorph disk is fixed firmly which means this area has no degree of freedom. Therefore, the radial mode of the transducer transfers to the flexure mode. The mobile elements move along the Pyrex shaft by the impact force generated by the flexure mode of the piezoelectric transducer. The motors are operated at their resonant frequencies. The dynamic properties of the motor have been intensively measured and analyzed according to the applied voltage waveforms at the resonant frequencies. As the sawtooth and rectangular voltage waveforms are applied, the velocity, the thrust force, and the velocity dependence of the mobile position are measured. The dynamic characteristics are also analyzed within a period of each wave using laser vibrometer. The velocity of the mobile is moderately constant along the shaft. The better dynamic characteristics are obtained in the case of applying the rectangular waveform.