To enhance the flight safety of aircraft with wing damage, this paper investigates the effect of asymmetric wing damage on aerodynamic and dynamic characteristics of aircraft and proposes an incremental fault-tolerant control method based on an improved predefined-time theory, thereby improving stability recovery and fault-tolerant performance. First, the effects of wing-tip truncation and perforation damage on aerodynamic performance are analyzed using CFD software. Second, based on the aerodynamic characteristics of damage effects, a six-degree-of-freedom nonlinear model of the aircraft with asymmetric wing damage is established. Three representative trim strategies are then investigated, and their applicability is discussed through case studies. Subsequently, the existing predefined-time control theory is improved to accelerate closed-loop system convergence and address the mismatch between theoretical convergence time and user-defined time. On this basis, an incremental trajectory fault-tolerant controller is developed for the damaged aircraft, and the stability and predefined-time convergence of the closed-loop system under wing damage are rigorously proven using Lyapunov theory. Finally, the effectiveness and superiority of the proposed incremental trajectory fault-tolerant control scheme are validated through both numerical simulations and real-time simulation experiments.

To address the deep-stall recovery problem of V-tail aircraft, this paper proposes a novel deep-stall recovery hierarchical strategy that combines Penalized Proximal Policy Optimization (P3O) reinforcement learning with a fast predefined-time incremental control approach. First, a six-degree-of-freedom nonlinear model of the V-tail aircraft is established, and the deep-stall recovery problem is formulated as a constrained Markov decision process. Second, the existing predefined-time control theory is improved to enhance the transient performance of state responses under given convergence time. Based on this improved theory and a nonlinear incremental dynamic inversion method, an angular rate controller is designed, which ensures that angular rate accurately tracks the decision commands within the user-defined time. The predefined-time stability of the controller is theoretically proven via Lyapunov stability theory. Subsequently, a decision-making network based on P3O is constructed to improve the safety during deep-stall recovery, where safety constraints are incorporated as penalty terms to guide the agent in generating safe recovery actions. Finally, a series of simulations and Monte Carlo experiments are conducted to validate the proposed strategy. The results demonstrate its superior performance in terms of rapidity, robustness, safety, and interpretability.

To address the disturbance of carrier wake and deck motion to carrier-based aircraft, this paper combines direct lift technology and incremental nonlinear control based on the predefined-time theory to improve the landing accuracy of carrier-based aircraft. Firstly, the full-state nonlinear dynamic equations of the aircraft are established, and the mechanisms and advantages of the direct lift control technology are analyzed. Secondly, an incremental control method based on the predefined-time theory is proposed, and an automatic landing controller for the carrier-based aircraft, consisting of the attitude stabilization loop, altitude control loop, and approach power compensation system, is designed based on this method. The designed automatic landing controller ensures that the tracking error of the carrier-based aircraft state converges to an adjustable bounded range within a predefined time, even under the influence of disturbances, thus enhancing its ability to rapidly track landing trajectory commands and deck movements. Moreover, this controller utilizes its robustness to reduce the impact of the carrier wake on the carrier-based aircraft. Subsequently, the predefined-time stability of the automatic landing closed-loop control system is rigorously proven under the Lyapunov stability theory. Finally, a series of real-time simulations verifies the effectiveness and superiority of the designed automatic landing controller.