Abstract: The kinematics and dynamics of the underactuated redundant manipulator are analyzed, and a dynamic manipulability measure is proposed for the underactuated manipulator when it is working in the full-actuated mode. Furthermore, a nonlinear control method is suggested for controlling the motion of the manipulator that is working in underactuated mode. This algorithm can control the motion in the configuration space that has higher dimensions than that of the input space, so the “self-motion” that is an intrinsic characteristic of the under-actuated redundant manipulator can be exhibited definitely in dynamics level. Based on the fact of this, an optimizing algo-rithm for improving the dynamic manipulability of the under-actuated manipulator is proposed. The simulation results on a planar four joints manipulator that has two passive joints had shown some aspects of the investigations.

Key words: Manipulators, Nonlinear control Dynamic manipulability, Selfreconfiguration, Underactuated