Development of Active Control for a Four-Axial Pneumatic Isolation System via High Speed on/off Valves

This study aims to develop the active control for the four-axial PWM (Pulse Width Modulation) pneumatic isolation system. A novel concept using parallel dual-on/off valves with PWM control signals is proposed to realize the active anti-vibration control and position control. In this thesis, on/off valves by PWM realized by software are used. Therefore, additional hardware circuit is not required to implement PWM.
In this study, we first derive the nonlinear mathematical model of the pneumatic isolation system. In the controller design, Fourier series-based adaptive sliding-mode controller with tracking performance is used for dealing with the uncertainty and time-varying problems of the pneumatic system.
The experiments of path-tracking control and the active anti-vibration control are implemented in the four-axial pneumatic isolation system under different loading conditions. Finally, in order to satisfy the demand of the practical application in pneumatic isolation system, the hybrid control that combines the path tracking control and active anti-vibration control is developed and verified through experiments under different conditions.