Effect of Gravity on Manipulation Performance of a Robotic Arm

The present paper introduces an evaluation of the manipulation performance of a robotic arm with respect to control accuracy and mechanical efficiency, taking into consideration the effects of gravity and the dynamic process between inputs and outputs in the robotic system. A measure based on the output controllability ellipsoid is proposed, which shows the relationship between the end-effector motion and the joint driving force. Computer simulations demonstrate the effects of gravity on the manipulation performance and the benefits of the proposed measure for the trajectory planning.