Study and Design of a Fractional-order Terminal Sliding Mode Fault-Tolerant Control for Spacecraft

In industrial systems, performance of a spacecraft is always affected by the presence of uncertainties and disturbances. In this paper, we study the application of a combination of FaultTolerant Control (FTC) designs based on fractional calculus and Terminal Sliding Mode Control (FOTSMC) for a spacecraft in the presence of external disturbances. The proposed controller shows better control performance compared to existing terminal sliding mode control (TSMC).Moreover, in our design, the control law does not need a fault detection and isolation mechanism. The sliding mode control protects controller against disturbances and uncertainties while the fractional calculus provides robust performance. The performance of the proposed fractional-order controller, as compared with other controllers, is provided via numerical simulations. The results clearly demonstrate better performance of the fractional order terminal sliding mode control for an actuator fault in comparison with the terminal sliding mode control. The analytical stability analysis of the closed-loop control system is also provided by the Lyapunov direct method for fractional-order system.