Robust finite-time control for spacecraft attitude stabilization under actuator fault

A finite-time convergent sliding mode control (SMC) scheme is developed to solve the problem of fault-tolerant control for a rigid spacecraft attitude stabilization manoeuvre in the presence of uncertain inertia parameters and external disturbances. A new terminal sliding surface is first presented. Based on the sliding manifold designed, a robust sliding mode controller is then derived for automatically compensating the external disturbances, uncertain inertia matrix, and even time-varying actuator faults. One feature of the proposed strategy is that the design of the fault-tolerant control does not require a fault detection and isolation mechanism to detect, separate, and identify actuator faults. Lyapunov stability analysis shows that finite-time convergence of spacecraft attitude orientation to the equilibrium point can be accomplished with great robustness to disturbance and actuator faults guaranteed. Numerical simulation results are also presented that not only highlight the closed-loop performance benefits from the control law derived here, but also illustrate the proposed procedures and their effectiveness when compared with a conventional SMC scheme for spacecraft attitude stabilization control.