Mathematical Model of Ultrasonic Motors for Speed Control

Abstract

Abstract In this article, a mathematical model of ultrasonic motors for speed control, which includes the non-linearity and approximation of the dead-zone in control input, is presented. The intrinsic properties of ultrasonic motors (high torque for low speed, high static torque, compact in size, etc.) offer great advantages for industrial applications. However, the speed property of ultrasonic motors has a strong non-linear property as well as the dead-zone effect in control input associated with load torque. These properties present serious problems for accurate speed control. This article presents a mathematical model represented by a sinusoidal function, which includes these properties. The model is simple and has good approximation of the non-linearity and time varying properties. The proposed speed model has been validated by experimental results.