Nonlinear Reference Shaping with Endpoint Position Feedback for Large Acceleration Avoidance in Reaching Movement

Abstract

The nonlinear reference shaping for manipulators used in ordinary living environments is proposed. It generates an intermediate reference position, and it is combined with control based on the virtual springdamper hypothesis. Initial acceleration is moderated by the reference position inserted between the original target and current endpoint position and by a secondorder lag filter. The endpoint position is fed back to prevent from excessive trailing force and large acceleration, resulting in smooth reaching movement and flexible behavior against external force. The feasibility of the concept of the proposed controller is confirmed through computer simulation on a planar 4-DOF manipulator.