Pneumatic force servo system based on disturbance observer

In order to design a low-cost pneumatic force servo system with large output forces, a scheme of a booster cylinder controlled by high speed solenoid valves is proposed. A nonlinear model of the system is established, in which the hysteresis of high speed solenoid valve is considered. In order to deal with parameter uncertainty and disturbances of noise and friction, a feed-forward control method based on a disturbance observer is proposed. A practical pneumatic force servo system is used to testify the feasibility of the proposed controller. The experimental results show that pneumatic force servo system based on the proposed controller has high force tracking accuracy and quick response.