A Hierarchical Evolutionary Trajectory Planner for Spacecraft Formation Reconfiguration

A hierarchical evolutionary trajectory planner (HETP) for spacecraft formation reconfiguration is presented. Two levels are included in HETP. The high-level planner performs global planning which includes configuration optimization and collision avoidance between spacecraft. The low-level planners design multiple optimal or near optimal trajectories which are separated one from another for each spacecraft by parameterizing the controls in terms of Chebyshev polynomials. Based on the attributes of the system dynamics, a flexible scheme is used to select final trajectories and to avoid collisions. Our approach scales well with the number of spacecraft by planning trajectories for each spacecraft in parallel. The high level and the low level can coevolve, and multiple trajectories can be generated simultaneously as alternatives. The control precision constraints which could reduce control errors are also taken into account. The experiments described here demonstrate the efficiency of the proposed algorithm.