Adaptive spacecraft attitude tracking control with guaranteed transient performance

In this paper, we concentrate on the problem of attitude tracking control with guaranteed transient performance for a rigid spacecraft subject to unknown inertia properties and exogenous disturbances. A promising solution to the problem under consideration is presented. Specifically, certain performance functions specified a priori by the designer are first introduced to impose desired transient and steady state performance specifications on the attitude tracking errors. Subsequently, by using an error transformation, the original attitude tracking dynamics with performance constraints are transformed into an equivalent unconstrained one whose robust stabilization is shown to be sufficient to achieve prescribed performance guarantees. Then, based on the transformed system, an adaptive controller is designed by incorporating the backstepping control and the adaptive technique. It is proven that the control algorithm developed can guarantee the stabilization of the transformed errors, and hence the achievement of the desired performance metrics, as well as the boundedness of all other closed-loop signals, without resorting to an exact knowledge of the inertia matrix and despite the presence of external disturbances. Besides detailed control design and rigorous closed-loop stability analysis, numerical simulations are finally performed on a microsatellite to testify the effectiveness of the proposed control scheme.