Dynamic event-triggered fault-tolerant control of rigid spacecraft with prescribed performance

This study proposes a fixed-time disturbance observer (DO)-based dynamic event-triggered fault-tolerant control (DETFTC) framework with prescribed performance for the attitude tracking of rigid spacecraft hampered by actuator faults, parameter uncertainties, and environmental disturbances. In contrast to conventional DO approaches that rely on initial conditions or upper disturbance bounds, this work introduces a fixed-time DO to accurately reconstruct lumped perturbations arising from exogenous disturbances, inertia uncertainties, and actuator faults. A DETFTC strategy is further developed to minimize unnecessary control signal updates while ensuring rapid and precise attitude tracking. Integrating fixed-time performance functions with barrier Lyapunov functions guarantees that attitude-tracking errors converge to predefined ranges within a bounded time. The proposed method ensures that all signals in the closed-loop system are practically fixed-time stable, with attitude tracking errors constrained within predetermined boundaries and Zeno behavior effectively excluded. Lastly, case studies are conducted to demonstrate the effectiveness and practical applicability of the developed methodology.