Active Vibration and Attitude Control of a Vibration Isolation Table with Pneumatic Actuators (A Modeling Method for the Redundant System of Actuators and Sensors)

Active control of a vibration isolation table using pneumatic actuators is studied in this paper. The vibration isolation table is supported by four pneumatic actuators at corners of the square rigid table. A 3DOF physical model of the vibration isolation table is constructed with taking account of redundancy of the actuators and sensors. We introduce a method to determine the air pressure of each actuator to minimize the error between the average pressure of the actuators and the air pressure of each actuator. The regulator for the pneumatic actuator is driven by a stepping motor. Characteristics of the transfer function from input pulse for the stepping motor to the air pressure of the actuator are investigated experimentally and the mathematical model of the actuator is constructed as a second order delay system. Type I digital servo system is applied to control the vibration and position of the vibration isolation table. Control performance of the system is verified experimentally and the results are shown in figures.