Industrial applications of pneumatic servo systems are growing at a rapid pace because of their low costs, reliability, safety, etc. In this thesis, experimental and theoretical study on a pneumatic servo system has been conducted using on-off valves and a pneumatic cylinder. A V/I converter has been designed for rapid rising and falling of the solenoid current, which significantly improves the positioning accuracy and settling time of the servo system by shortening the valve opening and closing time. Pulse width modulation was modified to operate the on-off valve more effectively. A state feedback controller which feeds back position, velocity and acceleration is used to control the system. The influence of controller gains on the system performance is studied to develop a scheme that automatically adjusts the gains using fuzzy logic theory. It is shown experimentally that the proposed fuzzy logic tuner works satisfactorily.
The effective area of the valve is an important parameter for a precise simulation of pneumatic systems. A new method of testing the valve effective area is proposed.
