Studies on Opto-Pneumatic Servo System. 2nd Report. Theoretical Analysis of Control System and Control Performance.

Abstract

An optical servo system is a novel and attractive control system which can be used in hazardous environments. In our previous paper, we built two types of optical servo system which consist of a photo-fluidic interface, two booster amplifiers and a pneumatic cylinder. One type is the cart position control system in which the optical signal is fed back directly and the other type is that in which the optical signal is fed back indirectly. It is strongly desired to analyze the control system in order to make the control performance higher and to design the control system. This paper describes a theoretical analysis of the tested optical servo system. First, the opto-pneumatic servo system and its operating principle are explained briefly. Second, an analytical model of the tested control system is proposed. And, it is shown that the static and dynamic characteristics predicted by the proposed analytical model agree well with the experimental results. Finally, the simulated results of the indirect feedback position control are compared with the experimental ones. It is shown that the positioning accuracy of ±0.15 mm which is almost the same as that in the usual electro-pneumatic servo system can be obtained.