Robust Flexible Predefined-Time Prescribed Performance Control with Beneficial Disturbance Utilization for Carrier-Based UAV Landing

Automatic carrier landing of fixed-wing UAVs remains challenging under deck motion, carrier airwake, gusts, and actuator faults. This paper proposes a robust flexible predefined-time prescribed performance control (RFPTPPC) framework with beneficial disturbance utilization (BDU). A control-oriented six-degree-of-freedom cascaded model with direct lift control is first established. To address the temporary infeasibility of fixed predefined-time PPC boundaries, direction-selective flexible boundaries restore the admissible attitude error region when the nominal envelope is threatened, while a smoothly coordinated recovery branch drives the error inward. An adaptive super-twisting extended state observer (ASTESO) reconstructs lumped disturbances in the cascaded loops. Using the ASTESO outputs, BDU evaluates each disturbance component, retains those that favor error convergence, and compensates for adverse components, thereby improving attitude tracking accuracy and maintaining PPC feasibility. Lyapunov analysis establishes practical predefined-time stability of the closed-loop system. Comparative simulations demonstrate improved trajectory tracking, attitude regulation, actuator coordination, and robustness under randomized landing conditions.