Pre-impact trajectory planning for minimizing base attitude disturbance in space manipulator systems for a capture task

Aimed at capture task for a free-floating space manipulator, a scheme of pre-impact trajectory planning for minimizing base attitude disturbance caused by impact is proposed in this paper. Firstly, base attitude disturbance is established as a function of joint angles, collision direction and relative velocity between robotic hand and the target. Secondly, on the premise of keeping correct capture pose, a novel optimization factor in null space is designed to minimize base attitude disturbance and ensure that the joint angles do not exceed their limits simultaneously. After reaching the balance state, a desired configuration is achieved at the contact point. Thereafter, particle swarm optimization (PSO) algorithm is employed to solve the pre-impact trajectory planning from its initial configuration to the desired configuration to achieve the minimized base attitude disturbance caused by impact and the correct capture pose simultaneously. Finally, the proposed method is applied to a 7-dof free-floating space manipulator and the simulation results verify the effectiveness.