This paper is concerned with the practical application of self-tuning control on the position control of a pneumatic servo cylinder. In this study, instead of establishing a nonlinear mathematical model of a pneumatic servosystem, system identification by the recursive least square method is applied to find the mathematical model, then a self-tuning controller is designed and implemented in a microcomputer to control the position of the cylinder. A desired time response of the cylinder position can be obtained by using a self-tuning controller with the pole-placement approach. The experimental results with the self-tuning controller are compared to those from the conventional PID controller. With the self-tuning controller, the effect of the variable load and the variation of the system parameters are reduced.
Hongming ChenZi-Yi ChenMing-Cheng Chung