Dynamic Model Identification for Ultrasonic Motor Frequency-Speed Control

The mathematical model of ultrasonic motor (USM) is the foundation of the motor high performance control. Considering the motor speed control requirements, the USM control model identification is established with frequency as the independent variable. The frequency-speed control model of USM system is developed, thus laying foundation for the motor high performance control. The least square method and the extended least square method are used to identify the model. By comparing the results of the identification and measurement, and fitting the time-varying parameters of the model, one can show that the model obtained by using the extended least square method is reasonable and possesses high accuracy. Finally, the frequency-speed control model of USM contains the nonlinear information.