Simplex Sliding Mode Control Strategies for Spacecraft Rendezvous Maneuvers

Space systems are subject to strict requirements in terms of relative position between two spacecraft and are controlled by actuators, which can perform limited output levels at low frequency. The aim of this work is the design of a sliding mode controller, which suitably combines simplex and super-twisting algorithms. This controller permits to reduce the number of thrusters required to control the spacecraft, the fuel consumption and the switching frequency at which the mono-directional actuators are turned on. The proposed control strategy can be easily converted in an on-board algorithm, with a minimum computational effort. Extensive simulations are carried out to validate the performance of the proposed sliding mode design.