Finite-time output feedback control for the attitude of the spacecraft without unwinding

This paper focuses on finite-time control in the attitude control system of the spacecraft based on the rotation matrix by using homogeneous method. Because the rotation matrix represents the set of attitudes both globally and uniquely, the system can overcome the drawback of unwinding which results in extra fuel consumption. In order to deal with actuator saturations, a finite-time controller is investigated by using the saturation function. Then, based on a novel filter, a finite-time output feedback controller with actuator saturations is designed. Theoretical analysis shows that the proposed controllers can make the attitude error converges to zero in finite time. Numerical simulations also demonstrate that the proposed control schemes are effective.