Model Predictive Control Strategies for Spacecraft Formation Flying Applications

Abstract. Formation flying missions require high performance orbital control strategies, which are based on the accurate analysis of the spacecraft relative dynamics and on efficient control techniques. Model Predictive Control (MPC) is a modern optimal control strategy that is very attractive for formation flying and rendezvous missions, mainly because of its ability to cope with constraints on control actions and dynamic state of the system. Every real space mission indeed imposes constraints, as for example the maximum control force a thruster system can apply, or the relative positions and/or velocities that satellites flying in formation should have to guarantee formation safety. MPC can take into account both control and state constraints directly in the optimal control action computation, resulting in a more efficient control system than other control strategies. In this paper we present a study on the MPC application to a formation acquisition maneuver for two space vehicles, taking into account two scenarios: a Leader-Follower formation and a Projected Circular Orbit formation. The performances of an MPC controller are compared with those of a LQR controller in carrying out the same maneuver, evaluating also the effects of the gravitational harmonics J2 , J3 and drag perturbations on the proposed maneuvers.