Analysis and measurement of lateral elliptic motion effect for an asymmetric disc-type ultrasonic motor

摘要

This paper presents an analysis and measurement method for studying lateral elliptic motion effect of an asymmetric disc-type ultrasonic motor whose stator is a circular disc with a bonded PZT plate serving as a drive. At the edge of the stator with a simple, fixed three-point support of a 120°-90°-150° configuration, there exists a coupled vibration wave with lateral elliptical motion so as to generate a driving force between the stator and the rotor. The equations of the lateral elliptic motion and the driving force are analytically formulated based on the wave equation on the circular plate, thereby obtaining the driving frequency and the revolution speed of the motor. The relationship between the ultrasonic stator and its boundary condition is investigated as well. The analysis shows that the circumferential edge with a 90° included angle is an optimal contact section for the placement of the rotor. Experiments using the laser vibrometer and photodetector are used to show the validity of the proposed analysis method.