Controller design for rigid spacecraft attitude tracking with actuator saturation

This paper investigates the attitude tracking control problem for rigid spacecraft with actuator saturations, inertia uncertainties and external disturbances. First, based on adaptive algorithm, a sliding mode control (SMC) law is designed to achieve accurate attitude tracking, and asymptotic convergence is guaranteed by means of the Barbalat lemma. Then, the spacecraft dynamic equation is optimized, and a novel method plays a crucial role toward ensuring stability robustness to actuator saturations in the control design. Using backstepping technique (BT) associated with extended state observer (ESO) or modified differentiator (MD), the corresponding SMC approaches are appropriately designed, which not only achieve a faster and more accurate response, better transient performance, but also afford stronger capability of resistance to inertia uncertainties, external disturbances and control input saturations. Finally, simulation results are presented to illustrate effectiveness of the control strategies.