Restructurable Guidance and Control for Aircraft with Failures Considering Gust Effects

This paper presents a procedure for designing a fault-tolerant guidance and control system for a damaged aircraft using the simultaneous online fault/wind estimation and the nonlinear restructurable guidance and control law. The algorithm employs an extended Kalman filter (EKF) and a nonlinear inverse dynamics (NID) controller with the singular perturbation method. The EKF, which is based on the six-degree-of-freedom nonlinear aircraft equations of motion, simultaneously estimates the aerodynamic derivative changes and the wind-velocity components. The NID controller computes the required control-surface deflections and engine thrust not only to stabilize damaged aircraft but also to enable the aircraft to track the reference trajectory using the estimated results in a gusty environment. The estimation algorithm is evaluated through flight-test data obtained by using the experimental aircraft. Numerical simulations are carried out to verify the guidance and control capability of damaged aircraft under gusty conditions.