Modelling and control scheme of the ball–plate trajectory-tracking pneumatic system with a touch screen and a rotary cylinder

For the multivariable and complicated ball–plate control system, in this study a touch screen and a rotary pneumatic cylinder are adopted instead of a camera and a step motor, respectively. A touch screen is utilised to collect the ball coordinates, and it is of high precision, rapid response and strong anti-interference ability. Using the rotary-cylinder position pneumatic servo mechanism to actuate the ball–plate system, it has high control precision, large speed variation range and good low-speed characteristics. Models of the rotary-cylinder servo mechanism and the ball–plate system are, respectively, built. For the non-linearity of the system, it is hard to attain good performance by using the traditional control method, so the controller is designed with a state observer and fuzzy control algorithm. Simulation results show that it has good dynamic and static characteristics with the proposed control method. And a hardware-in-the-loop (HIL) model is further built to realise the steady run of the system.