Modeling and simulation study of flexible space robot for capturing large flexible spacecraft

A future spacecraft, the target to be serviced by a space robot, is growing in size to meet ever more demanding mission requirements. Large flexible components, such as antenna reflectors and solar paddles, are inevitably mounted on the spacecraft. Due to the structure vibration, it is very challenging for a flexible space robot to capture and repair a large flexible satellite. In this paper, we derived the dynamic model and developed a closed-loop simulation system, to supply a means to verify key path planning and control algorithms. Firstly, the dynamic characteristics of different capturing stages (pre-capture, contact/impact, and post-capture) are analyzed. The topologies of a flexible space robot and the compounded system after it captures a large flexible spacecraft are then described using incidence and channel matrixes. Secondly, the recursive dynamic is formulated and numerical calculus method is used to solve it. The modeling and resolving code is programmed by C language, and verified with ADAMS model. Thirdly, the dynamic calculation block is implemented in Matlab/Simulink environment using S-function package, and the closed-loop simulation system is developed. Finally, dynamic simulation of on-orbital manipulating the target along a circle is performed. Some useful rules are then presented to suppress the vibration of the flexible structure.