摘要：Snare capture is a capture mode, which mainly relies on three flexible cables to enclose and then latch the target. Regarding the pre-impact phase of snare capture, this article presents a capture strategy for redundant space manipulator with the aim of improving reliability. It contains two steps: the attitude regulation of snare-type end-effector and the optimized control of space manipulator. In the first step, the contact model between grapple shaft and flexible cable is established based on the discrete flexible cable model. And then, with the purpose of reducing the peak value of contact force, a “safe contact region” is designed and the grapple shaft can get into it by regulating the end-effector’s attitude. In the second step, a description of the inertial properties perceived at the end-effector of space manipulator is provided first, and on this basis, the objective functions which aim to reduce the disturbance of the end-effector are established. Thereafter, the configuration of space manipulator is optimized by the null space method for its advantage of not affecting the regulated end-effector attitude. Finally, a simulation is carried out on a 7-degree-of-freedom space manipulator with snare-type end-effector and a target equipped with grapple shaft to prove the effectiveness of the proposed capture strategy.
关键词：Flexible cable; snare capture; space manipulator; minimum disturbance; null space
