Intelligent IMC-PID control for ultrasonic motor

Ultrasonic motor (USM) causes serious characteristic changes during operation and contains non-linearity caused by frictions. To compensate the characteristics, the internal model control - proportional integral differential (IMC-PID) control which requires only one parameter setting beforehand is widely applied to the control of ultrasonic motor. However, there are limitations of control performance on the conventional fixed-gain type IMC-PID control. So, in this paper we propose an improved method of variable gain type IMC-PID control combined with neural network (NN). In this proposed method, the identification method is adopted to overcome serious characteristic changes and neural network is used to compensate non-linearity. And, the effectiveness of the proposed method has been confirmed by experiments.