Variable gain type IMC-PID speed control for ultra-sonic motor

The PID control is widespread most as control methods of an ultra sonic motor (USM). However, setting three gains of the PID control beforehand is not so easy. On the other hand, an internal model control type PID (IMC-PID) control is very effective because it requires only one parameter setting beforehand. However, there are limitations of control performance on the conventional fixed-gain type IMC-PID control because USM causes serious characteristic changes during operation and contains non-linearity caused by frictions. In this paper, we propose the variable gain type IMC-PID combined with neural network (NN). In the proposed method, the identification method is adopted to overcome serious characteristic changes and NN is used to compensate non-linearity. The effectiveness of the proposed method has been confirmed by experiments.