Robust Hybrid Supervisory Control for a 3-DOF Spacecraft in Close-Proximity Operations

In this paper we propose a hybrid control strategy to solve the problem of rendezvous, proximity operations, and docking of an autonomous spacecraft in 3D. Due to the different constraints and tasks to perform, a hybrid systems approach is implemented to solve the problem in three phases: 1) rendezvous; 2) rendezvous with smaller relative distance; 3) docking phase; and 4) docked phase; with range and angle measurements. In this approach, we implement a supervisor that robustly coordinates the individual controllers to accomplish the whole mission. We also present the designs of these individual controllers that solve the appropriate control problems for the individual phases. Numerical results for both the nominal and perturbed case validate the hybrid control strategy for the spacecraft close-proximity mission.