Anti-vibration control of contactless planar actuator with manipulator

This paper addresses the anti-vibration control produced by manipulator movements of contactless planar actuator with manipulator (CPAM). The manipulator on top of the planar actuator has 2-DOF which provides precise linear and rotary movement of the end tip of the manipulator. The successful suppression of the vibration will improve the position accuracy of the CPAM. For the purpose of the anti-vibration control design, a platform of 3-DOF contactless planar actuator with 2-DOF manipulator has been designed and manufactured. The platform, that mimics the magnetic array of the planar actuator, is suspended by 9 voice coils which are distributed into regular array to simulate the topology of the planar actuator and will be used for gravity compensation and for manipulator platform control in 3-DOF: vertically and two tilting angles. The other 3-DOF is fixed by the suspension system consisting of 3 stiff rods. Nine inductive sensors are mounted on the base plate to measure the posture of the platform when the manipulator is working. The CPAM model is based on rigid body dynamics and movement of the manipulator is taken as a disturbance in the platform control. According to the concept of loop shaping, robust H infinity controllers for each of the DOF of the platform are then designed depending on the estimated disturbance force and torque from the manipulator. Control responses in 3-DOF are then presented. The results illustrate high positioning stability.