A controller design for spacecraft attitude maneuvering with control saturation based on L₂-gain

In this paper, a simple robust saturation controller is developed for attitude maneuver of a rigid spacecraft, in which external disturbances and control input constraint are simultaneously taken into account. Precisely, a class of novel nonlinear saturation functions, called power saturation function, is investigated to rigorously enforce actuator-magnitude saturation constraints. Although control smoothness is preserved at all times, it is important to note that the results of this paper that are derived with respect to magnitude saturation place no additional restrictions on the body inertias and make no other small-angle assumptions. The novelty of the approach is in the strategy to construct such a Lyapunov function that ensures not only stability of closed-loop system but also an L₂-gain constraint on the performance, which provides a closed-form solution for spacecraft attitude control problem, compared with the conventional methods. Finally numerical examples illustrate the effectiveness and robustness of the proposed controller.