Abstract: The drifting phenomenon of underactuated manipulator is exposed under harmonic input of actuated joints based on the nonlinear dynamic analysis of the systems. On the other word, when the actuated joints are droved by small oscillation, the passive joints of the underactuated manipulators will drift from its equilibration position. Based on this phenomenon, a close-loop control method with small amplitude oscillation is proposed. Furthermore, the artificial potential field technology was introduced to planning the motion of the redundant ma-nipulators, and an integrated motion-planning algorithm con-sidering obstacle avoidance for the underactuated redundant manipulator is suggested. Some simulations of planar 3-DOF manipulator with last one passive joint are shown some aspects of the research.

Key words: Artificial potential fields, Manipulators, Motion planning, Nonlinear dynamic, Underactuated, Dimensionality reduction, Early fault identification, Graph-implanted probability-based semi-supervised discriminant analysis, Manifold learning, Rotating machinery