Establishing the dynamic transfer function of a shaft-driving type ultrasonic motor by system identification

In this study, the experimental method for a novel shaft-driving type ultrasonic motor was developed. A stator of motor is a commercial available buzzer disk consisted of piezoelectric ceramic membrane bonded on a nickel alloy circular sheet. Via electrical-mechanical coupling characteristic, ultrasonic motor's driving mechanism is generated by 3 progressive bending waves reflected by hard screw constraints. Based on the design of signal measurement system and the basis of system identification theory, the dynamic transfer function was created which corresponds in converse piezoelectric effect using a single phase AC voltage power. The result exhibits the better estimation in dynamic transfer function than that of theoretical method.