Rapid vibration attenuation and height level compensation control for a pneumatic isolation table with quantized input

An active control in a pneumatic isolation table which is driven by on-off air valves is considered in the present paper. A control method for the table with quantized input action caused by the on-off valves has been proposed for rapid vibration suppression. The proposed method determines the control input by using the Lyapunov function for avoiding instability against the quantization of the control input. The method provides superior vibration attenuation performances to the conventional methods in some experiments. However, there remains height level offset after the vibration control by the previous method. In the present paper, a modified control method is proposed for attenuation of the height level offset by using the servo control. The effects of the modified method are verified by numerical simulations and experiments.