Spacecraft Attitude Stabilization Control Under Actuator Faults and Input Saturation

This paper addresses control input saturation, actuator faults, measurement error, external disturbances, and system parametric uncertainties problems in the context of spacecraft attitude maneuvers. Initially, utilizing a recursive adaptive back-stepping (ABST) approach, we design observers to deal with the adverse effects of additive measurement errors, parameter uncertainties, external disturbances, and actuator faults. Later, an anti-windup compensator is incorporated into the developed ABST controller to handle the effect of actuator saturation. We use Lyapunov stability analysis to establish a finite-time (FT) convergence of measured attitude, angular velocity, input compensator states, and disturbance observer states to a small neighborhood of zero. Tuning conditions for controller design parameters are derived utilizing Lyapunov analysis, which provides a theoretical foundation for controller stability. The simulation results demonstrate the effectiveness of the proposed control approach to ensure precise spacecraft attitude control despite challenging conditions.