Robust hybrid supervisory control for spacecraft close proximity missions

We consider the problem of rendezvous, proximity operations, and docking of an autonomous spacecraft. The problem can be conveniently divided into three phases: (1) rendezvous phase; (2) docking phase; and (3) docked phase. On each phase the task to perform is different, and requires a different control algorithm. Angle and range measurements are available for the entire mission, but constraints and tasks to perform are different depending on the phase. Due to the different constraints, available measurements, and tasks to perform on each phase, we study this problem using a hybrid systems approach, in which the system has different modes of operation for which a suitable controller is to be designed. Following this approach, we characterize the family of individual controllers and the required properties they should induce to the closed-loop system to solve the problem within each phase of operation. Furthermore, we propose a supervisory algorithm that robustly coordinates the individual controllers so as to provide a solution to the problem. In addition, we present specific controller designs that appropriately solve the control problems for individual phases and validate them numerically.