Robust adaptive attitude tracking for satellites with constrained control inputs

The attitude tracking control problem for satellites with constrained control inputs, external disturbances and uncertain inertia parameters is investigated in this paper. A bounded robust adaptive state feedback controller is designed by using properties of the hyperbolic tangent function. It is proved via Lyapunov stability theory that angular velocity errors of the closed-loop system tend to zero asymptotically, attitude errors converge to a preset small neighborhood of the origin by choosing controller parameters properly and designed inputs satisfy the constraint. The simulation results demonstrate that the effects of unknown inertia and external disturbances can be suppressed by the proposed approach under constrained control inputs.