An output feedback back-stepping attitude control for rigid satellite.

This paper presents the attitude control of a rigid satellite in the presence of the total uncertainty of inertia and external disturbance while only outputs of the system are measurable. Noticing the conditions, a new robust back-stepping control for the modified Rodrigues parameters model of the rigid satellite is proposed, at the same time the upper bound of the norm of the total uncertainty vector is estimated adaptively. Due to the inaccessibility of the angular velocity of the system, a finite-time extended observer is used to estimate the angular velocity and total disturbance. The robust stability of the control system is proved by the Lyapunov theory. Finally, a numerical simulation is presented to demonstrate the effectiveness of the proposed control method. [ABSTRACT FROM AUTHOR]