Autonomous rendezvous and docking maneuvers with Model Predictive Control strategies

Since the beginning of space era, rendezvous and docking maneuvers have been of great importance for the success of numerous missions. The operation of meeting two or more space vehicles in orbit is a need for many missions which require the assembly or supply of orbital platforms, debris removal, or sample return for interplanetary missions. Such maneuvers can be performed automatically in a feedback way, with numerous advantages over manual control. The objective of this thesis is to present the Model Predictive Control (MPC), an advanced controller, for rendezvous and docking maneuvers between two cooperative satellites in orbit and compare its behaviors and performances with those of a classical PID controller. After the description of the operating principle of MPC and PID control strategies and the dynamics equations of the relative motion between satellites in orbit, a realistic rendezvous and docking scenario is considered. The scenario involves a 3U CubeSat performing autonomously the final approach to a target orbiting station along the V-bar direction, and includes some of the typical environmental disturbances at LEO orbits (differential drag and J2). A software developed in Matlab has been used to carry out the numerical simulations with the two kinds of controller. Once the optimal parameters of the controllers have been found and verified, a 1000-run Montecarlo simulation for both types of controller has been carried out and results have been compared in terms of quality of the trajectory inside the approach cones, respect of docking requirements, and use of delta-V.