Vibration suppression for SCARA robot with magnetorhelogical damper by using switching control

A vibration suppression method using switching control is proposed for smooth motion control of SCARA robot in wafer transition. The wafer robot is composed of joints integrated with magenetorhelogical damper. Vibration often occurs when acceleration jump abruptly, especially in the end of operation period. The residual vibration decreases the safety of wafer operation and extends the settling time. Firstly, Vibration sources of the driving joints are analyzed. Strategy by using switching control is analyzed. And dynamics model of robot joint with elasticity element is established. Magenetorhelogical damper is introduced into the design of joint structure to suppress vibration. It could provide reliable suppression effectiveness. Control structure of joint with elasticity and MR damper is discussed. And a PD controller is applied into joint motion control. Frequency characteristic of the joint demonstrates the stability of the control loop. Finally, simulation is implemented to verify the effectiveness of the proposed method.