Cascade observer-based robust fault tolerant control for switched non-minimum phase VTOL aircraft

This paper focuses on the switched nonlinear non-minimum phase thrust-vector vertical take-off and landing (VTOL) aircraft model, and proposes a cascade observer-based robust fault tolerant control method to guarantee that the multi model faulty system outputs track desired signals effectively. Cascade observers are designed to estimate the unknown disturbance and fault of each flight mode. By using the coordinate transformation and feedback linearization, the original system of each mode is decoupled into two subsystems. Then, fault tolerant controller is designed to stabilize the tracking error system of each mode. Consequently, a common Lyapunov function is given for arbitrary switching, and the input to state stability (ISS) method is used to discuss the global stability. Simulation results show the efficiency of the proposed method.