Intelligent IMC-PID control for ultrasonic motor

Ultrasonic motor (USM) is an electronic motor which causes serious characteristic changes during operation and contains non-linearity caused by friction. For USM control application, proportional integral differential (PID) control is a widespread control method. But in practical process, setting three gains beforehand is not an easy work. On the other hand, the internal model control type PID (IMC-PID) which requires only one parameter setting beforehand, mainly used in process control, is more effective relatively. However, in USM control, there are limitations of control performance on conventional fixed-gain type IMC-PID control since USM´s characteristic changes and non-linearity caused by friction. So, in this paper we propose an improved method of variable gain type IMC-PID control combined with neural network (NN) named ldquointelligent IMC-PID for USMrdquo. In this proposed method, system 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.