Effects of kinematic force errors on robot task performance

This paper examines the effects of errors in applied force on robot force-controlled task performance. Two configuration-dependent effects of force errors are identified. Kinematic stability errors occur when the robot configuration is such that small inaccuracies in joint torque create relatively large robot link displacements. This sensitivity to torque errors can seriously inhibit task performance in certain configurations. Task performance can also be affected by errors in the endpoint force angle which can be significant for even small changes in joint torque. Performance maps are developed as tools to identify robot configurations sensitive to these errors. The effects of force errors are demonstrated in the performance of a planar peg and hole task by a three link manipulator under joint torque control