Joint Actuated Torque Optimization Technique Applied to Space Manipulators via PSO Algorithm

In this paper absolute nodal coordinate formulation (ANCF) was utilized to model space manipulator links and natural coordinate formulation (NCF) was adopted to model manipulator joints to develop the dynamic equations of a rigid-flexible coupling space manipulator system. Joint rotation trajectories containing the self-movement term were deduced from the predetermined end-point trajectory by inverse kinematics theory. Inverse dynamics of the manipulator system based on Lagrange multiplier in dynamic equations leads to joint actuated forces/torques applied to bearing shells and journals during the movement. Thus particle swarm optimization (PSO) algorithm with constriction factor can be employed to optimize the redundant self-movement term to obtain the minimum energy consumption of actuated torques, which forms a new joint actuated torque optimization technique applied to redundant space manipulators. The three-link planar manipulator was used to evaluate this method. Simulation results show that the proposed method is effective in the end-point trajectory tracking and in reducing energy consumption; the computed joint torques obtained are well continuous and suitable for practical engineering.