A Finite Time Adaptive Robust Regulation Control of Spacecraft under Limited Measurements

This paper establishes a finite time robust controller for the attitude stabilization of the rigid spacecraft. The spacecraft is subjected to inertia matrix uncertainties, external disturbances, and inaccessibility of the angular velocity measurements. The proposed controller is developed by employing a non-singular fast terminal sliding manifold. The bound on the uncertainties are unknown; therefore, the adaptive law is incorporated in the control design to estimate the controller gains. The angular velocity is estimated using a finite time second-order differentiation observer. The output of this observer is then implemented in the proposed controller as state feedback. The closed-loop stability analysis affirms a finite time convergence of sliding manifold, and the system states to the origin. The numerical analysis demonstrates the effectiveness of the proposed closed-loop control system performance under the aforesaid constraints and uncertainties.