An active and passive combined fault-tolerant control approach for UAV with the control surface fault

In this paper, the fault-tolerant control (FTC) problem of fixed-wing unmanned aerial vehicle (UAV) with control surface structural damage is studied. An active-passive combined FTC algorithm based on sliding mode and adaptive control is proposed. Considering that the UAV is required to be instantaneously stable in the initial stage of the fault, a one-way auxiliary surface sliding mode controller based on fast dual power reaching law is adopted. During this period, the nonlinear recursive least squares method is used to identify the aerodynamic parameters of the UAV after the fault. Then, an adaptive control combined with aerodynamic parameter identification is designed to actively compensate for the fault. In addition, a hardware-in-the-loop simulation platform is developed to verify the active and passive combined FTC method. The simulation results show that the algorithm reduces the control error of the UAV after the fault and improves the robustness and reliability. This method provides a reliable technical guarantee for the safe flight of UAV under the condition of structural damage of control surface and has important practical significance for improving the reliability and safety of UAV.