A Novel Collision-Free Detumbling Strategy for a Space Robot with a 7-DOF Manipulator in Postcapturing Phase

Space robots are widely used for on-orbit capturing. After capturing a rotational non-cooperative target, its momentums produce unpredictable movements for the resultant space robot-target compound system. In order to address this problem, a collision-free detumbling strategy (CFDS) is proposed for space robots with a single 7-degree-of-freedom (DOF) manipulator. First, an acceleration potential field (AccPF) is presented for planning detumbling velocity trajectories, which guide the compound system to terminal rest while guaranteeing collision avoidance in dynamic environments. Energy conservation and acceleration limitations are considered in the trajectory generation. Afterwards, with a radial basis function neural network (RBFNN) approximating the target's uncertain dynamics, an adaptive control scheme is established to precisely track the planned detumbling velocity trajectory. Furthermore, system stability is certified by a Lyapunov function. The effectiveness of the CFDS is eventually validated by simulations.