Experimental tracking control for pneumatic system

Pneumatic system has many advantages, such as simple, reliable, low-cost, long life, etc. These make it to get rapid development and widespread application. But the complexity of the gas through the valve port and the friction between the cylinder and piston make it difficult to establish exact mathematical model, and to control the pneumatic system with high precision. We proposed an adaptive backstepping controller for a pneumatic position servo system based on the proportional valve. The controller was designed using backstepping method and assuming a third order linear model of the pneumatic system with unknown parameters. A parameter adaption law was developed to adjust the parameters and to track the reference output with high precision. The experiments were conducted to show the effectiveness of the proposed method. The comparison was made between the proposed method and two existing variable structure control methods to show the proposed method possessing better tracking accuracy.