Geometric robust adaptive control for satellite attitude tracking with reaction wheels

This study proposes a new robust adaptive tracking controller for satellite attitude dynamics with reaction wheel assembly. With the attitude kinematics represented by rotation matrix, the attitude control system is formulated to accommodate bounded disturbances and uncertain moment of inertia. The associated error dynamics are developed directly in SO(3) from geometric mechanics. Almost global asymptotic stability is formally proved in the sense of Lyapunov by using the geometry. The proposed controller is then applied to both numerical simulations and hardware experiments. It works well for our own developed spacecraft testbed for three experimental scenarios, even with disturbances/uncertainties caused by offsets of the center of mass and air-bearing. The selection of proportional gain dominantly affects the characteristics of attitude tracking. According to numerical simulations and hardware experiments, the proposed controller performs well, even when the measurement accuracy of angular velocity is low.