Cooperative motion planning for multiple flexible spacecraft via an RRT∗-based approach

In this paper, the rapidly-exploring random tree star (RRT∗) algorithm is developed for the motion planning of multiple rigid-flexible spacecraft, each of which consists of a rigid hub and flexible appendages. A series of strategies including multiple path generation and pruning are developed based on the RRT∗ algorithm to achieve an autonomous motion planning of multiple agents. In particular, an inter-spacecraft rewiring algorithm is proposed to address the interference among multiple spacecraft. Furthermore, a 3D-grid-based spatial indexing method is designed to increase the efficiency of the algorithm, and the linear quadratic regulator (LQR) is used to achieve the optimal fuel consumption and vibration suppression of flexible appendages. To show the effectiveness of the algorithm, both theoretical analysis and numerical simulations are presented for an on-orbit assembly mission of multiple flexible spacecraft.