Auto Tuning Control for Pneumatic Servo System Using Fuzzy Identifier.

The pneumatic servo-system has non-linear elements such as compressibility of air, friction between cylinder and piston. The control scheme with fuzzy inference is effective for such non-linear plant. However, the conventional fuzzy control has troubles in the shortage of adaptability and learning ability. Moreover, it seems difficult to attain the satisfactory control performance only by using the qualitative information of the plant. In this paper, we propose the new control scheme with fuzzy inference. In the proposed method, we compose the controller with the linear approximate model of the plant, which is one of the available information of the plant. In addition, the unknown controller parameters are identified by the fuzzy identifier and the shape of the membership function is automatically tuned to consider the effect of non-linearity. The effectiveness of the proposed scheme is confirmed by experiments using the existent pneumatic servo-system.