Kinematic analysis of precision planar manipulator on silicon

Abstract

A control architecture for the precision planar link mechanism on silicon, the semi-closed-loop feedback system, is proposed. Each joint is controlled in an open-loop manner using a stepping micromotor. The positioning accuracy of the control system depends on the kinematics of the mechanism, since no feedback loops concerned with the controlled variables exist. To investigate the feasibility of the control system, several kinematic issues are analyzed. The authors solve the inverse kinematic problem for this mechanism. They discuss the effect of joint clearances on the positioning accuracy on the platform. They derive the relation between the actuator resolutions and the attainable positioning accuracy of the platform. The final result revealed the tradeoff relation between the positioning accuracy of the platform and its working area. Since the necessary output torque also depends on the selection of kinematic parameters of the system, the design of micromechanical systems should be done based on the tradeoff relations among the actuator torques, positioning accuracies, working area, etc.