Force control of ultrasonic motor by the control of amplitude of sine-wave electric signals

摘要

The ultrasonic motor (USM) has unique characteristics, light weight, low speed and high torque, and we think it is efficient to use USM when we develop the light and compact mechanisms. In case of using USM instead of DC motor, a forced control is demanded in USM. However, USM presently can work only for position control or velocity control. In this paper, we propose the force control system of the ultrasonic motor. USM is driven by two different phase sine-wave electric signals which produces the traveling waves in the stator. The traveling waves generate its torque in its rotor. Torque generated by the traveling waves is decided by the sine-wave electric signals, especially amplitude and frequency. In this paper, we investigate force control of USM by the control of amplitude and frequency of sine-wave electric signals.