Resilient fixed-time trajectory tracking for quadrotors under hybrid sensor/actuator faults and delays

This paper proposes a robust fault-tolerant control technique for quadrotor position and attitude tracking. The proposed architecture simultaneously addresses external disturbances, modeling uncertainties, concurrent sensor and actuator faults, and state/input time delays. To this end, a comprehensive Fault-Tolerant Control (FTC) framework is developed based on a Fixed-Time Nonsingular Fast Terminal Sliding Mode (NFTSM) controller, whose design directly accommodates all the aforementioned challenges. The stability and performance of the proposed method are rigorously established through Lyapunov-based analysis. Its practical feasibility is validated via high-fidelity numerical simulations. Furthermore, real-time hardware-in-the-loop (HIL) experiments are conducted on a Speedgoat target machine. The obtained results are systematically compared against those achieved by two contemporary advanced control techniques. Comparative analysis demonstrates that the newly developed controller ensures rapid and accurate trajectory tracking while guaranteeing fixed-time convergence. The inherent NFTSM structure of the design proves highly proficient in attenuating oscillatory behavior and enabling reliable navigation through complex trajectories under the aforementioned adversarial conditions.