Semi-active vibration control for SCARA robot using magnetorhelogical damper

For smooth operation of SCARA robot for wafer transition, a new method using magenetorhelogical damper for vibration suppression is proposed. Vibration often occurs when the acceleration decrease or increase abruptly. Especially in the end of an operation period, the residual vibration decreases the safety of wafer operation and extends settling time. Firstly, Vibration sources are analyzed. And dynamics model of robot joint considering elasticity is established. Magenetorhelogical damper is introduced into joint structure to realize vibration suppression by physical mean. It could provide a reliable suppression effectiveness. Control structure of joint with elasticity and MR damper is discussed. A PD controller is applied into joint motion control to a desired movement. Frequency characteristics of the joint with MR damper are analyzed. Finally, a simulation is implemented to verify the effectiveness of the proposed method.