Multivariate Control Design Considering Quantization Error and Input Time-Delay for Pneumatic Isolation Table

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 exhibits vibration attenuation performances that are superior to the conventional methods in some experiments. However, this method suppresses vibrations in only the vertical direction. Therefore, improvement of the vibration suppression performance is required in not only the vertical direction but also the roll and pitch directions. In the present paper, a conventional method is extended to a multivariate control system. The effects of the extended method are verified by numerical simulations and experiments.