Adaptive Fault-tolerant Control Method For Carried-based UAV Automatic Landing

The failure of carrier-based UAVs will directly affect landing results in the actual landing process,which is a major difficulty in the automatic landing control technology.Aiming at the problem of automatic landing of UAVs with faults,the adaptive fault-tolerant control of automatic landing is studied in this paper.The main research contents are as follows.According to the parameters and motion equations of the carried-based UAV,the mathematical model of the UAV is established,including the non-linear model and the linear model.The automatic landing control system without fault-tolerant control is used to analyze the landing process with complex environmental disturbance,which lays a foundation for the design of adaptive fault-tolerant control system for automatic landing later.The failure modes of UAV are analyzed.The effects of vertical tail damage and actuator stuck are further analyzed.Vertical tail damage changes the aerodynamic parameters of UAV.The model parameters of the carrier-based UAV are uncertain obviously,so that the safe landing is failure to ensure.The actuator stuck makes the UAV control input unable to reach the expected value,affecting the landing process.Considering the uncertain change of model parameters of carrier-based UAV when vertical tail damage occurs,the adaptive fault-tolerant control method is introduced into the automatic landing control system.Theadaptive fault-tolerant control system for automatic landing includes guidance law and adaptive fault-tolerant flight control system.The state feedback output tracking controller is the nominal controller of the flight control system.Its parameters are updated continuously by the adaptive law,so that the UAV can land safely and accurately even if the vertical tail is damaged.Based on the redundant structure of the elevator and aileron,an adaptive fault-tolerant control system for automatic landing is designed for the elevator and the aileron stuck.In order to relax the model matching condition,the output feedback output tracking nominal controller is deduced from the control structure of state feedback output tracking.Combined with guidance law,flight control system based on output feedback output tracking adaptive fault-tolerant control constitutes an automatic landing adaptive fault-tolerant control system,which makes the UAV landing safely and accurately when the elevator or aileron is stuck.