Finite-time Disturbance Observer Based Attitude Stabilization Control under Actuator Failure

In this paper, a finite time fault-tolerant control problem is investigated for the spacecraft attitude stabilization control issue, which is subject to external disturbance torques and actuator failures. The approach is developed in the framework of observer based controller design. As a stepping stone, a simple and novel finite-time disturbance observer is first designed to reconstruct the synthetic uncertainty deriving form actuator failures and disturbances, by which the synthetic uncertainty is also compensated or restricted. Then, an simple finite-time attitude stabilization controller is investigated to enforce the closed-loop attitude control system to converge to the origin in finite time by using the estimated information from the proposed observer. In addition, the detailed derivations of the developed approaches are provided, along with a complete proof for the finite-time stability using Lyapunov method and homogeneity system theory. Finally, a simulation example for a rigid spacecraft model is carried out to verify the effectiveness and superiority of the proposed attitude control approach.