Quick Response Valve for Active Control of Pneumatic Vibration Isolation Tables

Active control of pneumatic vibration isolation tables requires extreme preciseness, due to the rapid growth of the demand for well performing precision positioning stages. And in order to meet this need, this paper proposes a new type of pneumatic valve for the control of air flow rates supplied into the air spring of the vibration isolator. Valves in general, have certain nonlinearities which degrade the precision of the control of air flow rates. Since the air flow rates are mainly dependent of the poppet position, the new valve equips an internal position sensor. Using this sensor, a poppet position inner feedback (FB) control, as well as a model based feedforward (FF) control is introduced in the control system. This method compensates for the air disturbance force to the poppet position and allows fast control of the pressure inside the air spring. The effectiveness of the proposed system is demonstrated through pressure tracking experiments.