Spacecraft attitude maneuvers using composite adaptive control with invariant sliding manifold

An adaptive control strategy is developed for spacecraft attitude tracking maneuvers, in the presence of structured uncertainty in the spacecraft inertia parameters. The proposed strategy incorporates a composite parameter update law, which guarantees global asymptotic stability of the overall closed-loop system. A stability analysis is performed using Lyapunov´s direct method, in conjunction with Bar-balat´s lemma. The asymptotic convergence results provided by this control strategy require persistently exciting reference trajectory commands. Simulation results are provided which demonstrate the performance of the proposed adaptive control design for a rigid spacecraft tracking a time-varying reference trajectory.