Coordinated hierarchical control of space robotic safe manipulation with load sharing

This research explores an integrated control technique for a dual-armed space robot that has captured a tumbling satellite. The compliant behavior for safe manipulation in-orbit is achieved using the external impedance at the target level. First, considering the control moment constraints imposed on the target body, a fast detumbling strategy is proposed using dynamic movement primitives method with normalized time. Following the capturing of a non-cooperative target, a coordinated hierarchical control scheme is developed with multi-arm space robotic dynamics modeling to direct the space robot in carrying out the pre-planned detumbling strategy. The proposed control scheme incorporates external impedance, internal force control and load sharing. Finally, numerical simulation with a sample case of two collaborative seven-degree-of-freedom space robotic arms capturing a tumbling target satellite verifies the viability and efficacy of the presented control strategy.