Revolution Speed Characteristics of an Ultrasonic Motor Estimated from the Pressure Distribution of the Rotor

Abstract

Using a two-dimensional elastic contact theory, the pressure distribution on the area of contact between the rotor and the stator vibrator of an ultrasonic motor is calculated. In this calculation, the stator vibrator and the rotor are assumed to be a rigid body and an elastic half-space, respectively. The no-load revolution speed of the motor using the calculated pressure distribution is estimated, and is compared with the measured speed. As a result, it is proved that the revolution speed can be estimated by using the calculated pressure distribution if the assumption is satisfied.