UC Santa Cruz

A hybrid control methodology is presented for autonomous rendezvous, proximity operations and docking of a pair of spacecraft. For the theoretical development of the control algorithms, the dynamics of the spacecraft are modeled using the Clohessy-Wiltshire-Hill equations, which result in a linear system of relative motion equations. Only in-plane motion is considered, resulting in a two-dimensional system, and the control input is the acceleration vector of the active spacecraft, constrained by a maximum thrust value. Individual controllers are designed for different phases of the of approach and transitions are governed by a hybrid supervising algorithm. The hybrid control algorithm is implemented both in MATLAB, using a simplified dynamic model, as well as in actual spacecraft flight code and tested in a high-fidelity spacecraft simulation test environment.