Two fault-tolerant control schemes for spacecraft attitude stabilization with external disturbances are proposed in this paper. The approach is based on integral-type sliding mode control strategy to compensate for actuator faults without controller reconfiguration. Firstly, a basic integral-type sliding mode fault-tolerant control scheme is designed so that sliding manifold can be maintained from the very beginning. Once the system enters the sliding mode, the dynamics of the closed-loop system with actuator fault is identical to that of the nominal healthy system. Secondly, the integral-type sliding mode faulttolerant controller is incorporated with adaptive technique to accommodate actuator faults so that the required boundary information can be relaxed. The effectiveness of the proposed schemes against actuator faults is demonstrated in simulation.

This paper addresses the finite-time fault-tolerant attitude stabilization control problem for a rigid spacecraft in the presence of actuator faults or failures, external disturbances, and modeling uncertainties. First, a basic fault-tolerant controller is proposed to accommodate actuator faults or failures and guarantee local finite-time stability. When there is no a priori knowledge of actuator faults, disturbances, and inertia uncertainties, an online adaptive law is proposed to estimate the bounds of these uncertainties, and local finite-time convergence is achieved by an adaptive fault-tolerant controller. In addition, another adaptive fault-tolerant control scheme is derived that explicitly takes into account the actuator saturation. The proposed attitude controller provides fault-tolerant capability despite control input saturation and ensures that attitude and angular velocity converge to a neighborhood of the origin in finite time. Finally, simulation studies are presented to demonstrate the effectiveness of the proposed method.

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