# Fault-Tolerant Control for Carrier-Based Aircraft Based on Adaptive Fuzzy Sliding-Mode Method
###### Abstract  
Carrier-based aircraft landing involves complex system engineering characterised by strong nonlinearity, significant coupling and susceptibility to environmental disturbances, and autonomous landing of carrier-based aircraft under fault states is even more challenging and riskier. To address the control-system problems of loss of efficiency and performance due to actuator faults and performance degradation due to various unknown disturbances, presented here is fault-tolerant control for carrier-based aircraft based on adaptive fuzzy sliding-mode fault-tolerant control (AFSMTFC). First, three models are built (the carrier-based aircraft fault model, the carrier air wake model and the deck motion model), and the control framework of the autonomous landing control system is introduced. Next, a longitudinal and lateral flight channel controller comprising an adaptive fuzzy network, adaptive laws and a sliding-mode controller is designed using the AFSMFTC method. The adaptive fuzzy network implements fuzzy approximation for the sliding-mode switching terms to further offset errors induced by unknown disturbances, the adaptive laws compensate for actuator faults, and the sliding-mode controller ensures tracking of the overall flight path. Furthermore, the stability of the fault-tolerant method is demonstrated using the Lyapunov function. Finally, simulation and comparative experiments show that the proposed fault-tolerant method has outstanding control performance and strong fault-tolerant capability, thereby providing an effective and feasible solution for designing an autonomous landing system for carrier-based aircraft under fault states. carrier-based aircraft; adaptive fuzzy control; sliding mode; fault-tolerant control +
Footnote †: journal: Applied  
to complex flight environments and large variations in dynamic pressure in operational missions, leading to serious degradation of system performance and posing direct threats to landing safety. In light of the above, there is an urgent need to study fault-tolerant control (FTC) for CBA. In recent years, various FTC strategies based on advanced control theory have been applied increasingly to the design of flight controller subsystems because different models and relevant requirements of control quality are becoming increasingly complex, leading to visible achievements [24; 25; 26]. [PERSON] et al. designed a fast adaptive terminal sliding-mode fault-tolerant controller for hypersonic flight vehicles to ensure limited state stability of the system with faults [27]. [PERSON] et al. provided an observer-based passive FTC programme for the power system of near-space hypersonic flight vehicles with uncertain parameters and actuator faults [28]. [PERSON] et al. designed a passive FTC method for unmanned aerial vehicles (UAVs) using dynamic inversion and robust integral technology of error signals to solve the efficacy failure of UAV actuators, and they proved the applicability of the method via simulations [29]. [PERSON] et al. designed an FTC solution based on a linear active disturbance rejection controller to solve the loss fault of rudder surfaces on UAVs, and they realised effective compensation for faults [30]. [PERSON] et al. designed an FTC strategy combined with an extended-state observer and sliding-mode control, which realised accurate compensation and effective control for carrier air wake turbulence via an extended-state observer; they also introduced a high-order linear differential tracker to obtain the required differential signals, and they verified it via simulation [31]. However, all the aforementioned studies were focused on passive FTC, which can reduce the sensitivity of the controlled system to faults by enhancing the robustness of the controller. Although neither fault diagnosis nor control reconstruction is needed, all types of possible faults must be known beforehand, which makes the controller relatively conservative and limited in its fault-tolerant function.