Stable Model Predictive Strategy for Rendezvous Hovering Phases Allowing for Control Saturation

Abstract : This paper presents a model predictive control strategy for the hovering phases of the impulsive spacecraft rendezvous problem producing a convergent sequence of relative trajectories, even under propellers saturation constraints. Adopting a linearized dynamics for the relative spacecraft dynamics , we present a parametrization of the relative trajectories. This parametrization and the constraints describing the hovering zones are employed in the formulation of the impulsive fuel-optimal control strategy, which is then proved to be stable. Numerical methods are proposed to solve the optimization problems characterizing each call of the controller. Finally, hardware-in-the-loop simulations using a synthesized LEON3 microprocessor and linear and disturbed nonlinear models for the relative dynamics are performed to assess the efficiency and robustness of the proposed approach.