Abstract
As electronics represented by computers makes progress, comparable actuators of small size and high-speed response are in strong demand. This ultrasonic motor is based on an utterly new principle where the rotating force is obtained by an ultrasonic vibration. It is greatly noticed as the actuator of this age because it has a very large torque per unit volume and an excellent controllability as compared with existing motors which are operated by the interaction of an electric current and a magnetic field. Two types of ultrasonic motors and their driving circuits have been developed. One is the ring type which allows uniqe applications, and the other is the disk type, which is easy to support, having wide general uses. This paper describes the principle of operation, construction, driving circuit, etc. of these ultrasonic motors.
