Finite-time spacecraft attitude control under input magnitude and rate saturation

This paper addresses attitude-stabilizing control for rigid spacecraft with actuator magnitude and rate saturation (MRS). Firstly, a continuous dynamical system is introduced to model the actuator MRS. Rigorous analysis is given to demonstrate that the model's output can always meet the MRS constraints if the control scheme applied to the model derived here is continuous. Then, by using the proposed MRS model and the homogeneity property, two attitude-stabilizing control laws are presented. The measurement of angular velocity is required in the implementation of the first control law, but this requirement is unnecessary in the second one. The local finite-time stability of the resulting closed-loop system is ensured by employing the Lyapunov approach. Finally, several simulation examples are presented to validate the efficiency of the proposed method.