Natural self motion of a robotic limb with single degree-of-redundancy

The self motion of a kinematically redundant robotic limb with single degree of redundancy is analyzed, focusing thereby on the nonlinear self-motion component. The role of this component has been completely ignored in past studies on self motion. It is shown that Jacobian pseudoinverse-based resolution - the usual resolution method for nonlinear self-motion - yields poor dynamic performance. A special type of self motion is identified based on the natural metric on the self-motion manifold and the energy conservation principle. This type of self motion is shown to have superior dynamics in terms of torque requirement and to avoid abrupt fluctuations in acceleration in the vicinity of singular points.