Fixed-Time Adaptive Fuzzy Fault-Tolerant Attitude Control for Tailless Aircraft Without Angular Velocity Measurements

This article introduces a novel adaptive fuzzy fault-tolerant controller designed for tailless aircraft's attitude tracking problem, even in the absence of angular velocity measurements. The controller addresses challenges posed by external disturbances, model uncertainties, and actuator faults. Initially, we propose a fixed-time sliding mode differentiator to estimate unmeasured angular velocity. Model uncertainties and external disturbances are approximated using fuzzy logic systems. Subsequently, a nonsingular fixed-time adaptive fuzzy fault-tolerant control scheme is developed based on the backstepping theory, which actively mitigates the impact of actuator faults, resulting in superior attitude tracking performance. The theoretical foundation of the proposed control scheme guarantees the boundedness and convergence of all closed-loop attitude control system states to a confined region around the origin within a fixed time. Notably, this convergence is achieved regardless of initial errors. Finally, simulation examples are presented to verify the effectiveness of the estimator and controller.