Adaptive Integral-Type Terminal Sliding Mode Fault Tolerant Control for Spacecraft Attitude Tracking

In this paper, the attitude tracking control for a spacecraft system based on a novel adaptive integral-type terminal sliding mode fault-tolerant control strategy is investigated. First, a basic fault-tolerant control scheme is designed to ensure the spacecraft attitude tracking performance in the presence of the actuator fault, external disturbance, and actuator saturation when the rotational inertia of a spacecraft system is known. Second, combined with adaptive laws, a modified fault-tolerant control scheme is proposed to compensate the actuator fault and system uncertainty which contains external disturbance and the inertia uncertainty, separately. The actuator fault is compensated more directly and accurately. The benefits of this approach are that the proposed control scheme can enable the merits of the integral-type terminal sliding mode control, such as nonsingularity, fast convergence speed, and small steady-state errors. Finally, the simulation results are given to demonstrate the effectiveness of the proposed fault-tolerant control schemes.