Synchronous position control strategy for bi-cylinder electro-pneumatic systems

Pneumatic systems have been widely used in industrial applications because of their well-known advantages. However, pneumatic systems possess several disadvantages that include strong non-linearity and low natural frequency. These drawbacks make it difficult to obtain satisfactory control performances in comparison to hydraulic and electromechanical systems. In this paper, the fundamental characteristics and nonlinear synchronous control strategy of pneumatic systems are studied. A two-layer sliding mode synchro-system based on friction compensation is applied to electro-pneumatic cylinders and a synchro-PID controller is utilized for position tracking. To validate the developed strategy, experiments with bi-cylinder electro-pneumatic systems were performed. The experimental results demonstrate that the synchronous position control scheme is effective in terms of accuracy and robustness.