Modifying the driving method of Thin Ultrasonic Motor

Abstract

A thin ultrasonic motor which was originally developed for a calendar drive unit was further utilized for watch hands drive unit. Driving watch hands requires lower power consumption and shorter driving time compared to driving a calendar. The trajectory of the stator tip was modified by changing the phase difference between the two vibration modes, and contact angle of the stator with respect to the rotor was optimized to achieve lower power consumption and shorter driving time.