An Overview of the Control Methods for Ultrasonic Motor

Compared with traditional electromagnetic motors, ultrasonic motors have many unique performances, such as low speed and high torque, fast response, high torque volume density and good control performance, which make them suitable for high-precision instruments and equipment drivers. However, due to the non-linear time-varying characteristics of ultrasonic motor, there is no mature theory of ultrasonic motor and servo control scheme. In this paper, the principle and characteristics of ultrasonic motor are introduced firstly. Then, the common control strategies of ultrasonic motor are introduced in detail, including PI control, fuzzy control and neural network control. Finally, the existing control methods are summarized and the advantages and disadvantages of various control methods are analyzed.