Gain-Scheduled Passive Fault-Tolerant Control Design for Dual-System UAV Transition Flight

Dual-system UAVs with vertical take-off and landing capabilities have become increasingly popular in recent years. As a safety-critical system, it is important that a dual-system UAV can maintain safe flight after faults/failures occur. This paper proposes a gain-scheduled passive fault-tolerant control (PFTC) method for the transition flight of dual-system UAVs. In this novel FTC design method, the model uncertainties arising from the loss of control effectiveness caused by actuator faults/failures, for the first time, are treated as model input uncertainty, allowing us to use multiplicative uncertainty descriptions to represent it. The advantages of the proposed method consist in significantly reducing the number of design points, thereby simplifying the control synthesis process and improving the efficiency of designing the FTC system for dual-system UAV transition flight compared with the existing FTC design methods. As a general method, it can be applied to the design of FTC systems with multiple uncertain parameters and multiple channels. The developed passive FTC system is validated on a nonlinear six-degree-of-freedom simulator. The simulation results demonstrate that the gain-scheduled structured H infinity (GS SHIF) PFTC system provides superior fault tolerance performance compared with the LQR and structured H infinity control systems, thereby showcasing the effectiveness and the advantages of the proposed GS SHIF PFTC approach.