Optimal detumbling trajectory generation and coordinated control after space manipulator capturing tumbling targets

This paper studies a shortest-time dissipation trajectory of a tumbling target after being captured by a space manipulator. A time-optimal control problem (OCP) that considers target attitude motion bounds as well as interaction torque limits at the grasping point is formulated. Then, the state and input inequality constraints are represented as extended dynamical sub-systems and saturation functions, respectively. Thereby, the OCP can be solved using the Calculus of Variations method with a highly accurate solution. Additionally, a coordinated controller using reference accelerations is proposed for the space manipulator, which guarantees that both the target and base spacecraft of the space manipulator can track desired trajectories. Numerical simulations demonstrate the effectiveness of the proposed method.