Abstract:

A reconfigurable flight control system for folding wing air vehicles is described. The approach combines real-time physical model identification with nonlinear dynamic inversion (NDI). It could solve the problem such as severe change of aerodynamic characteristics or influences of atmospheric disturbances during the primary stage of flight, and fulfill the high robustness requirements. The aerodynamic characteristics are identified  by the two-step method which consists of a separate state estimation step and an aerodynamic coefficients identification step instead of the one step method. The two-step method is based on iterated extended Kalman filter and fading memory least squares method which is easy to achieve online. The sensitivity of NDI to modeling errors is eliminated by making use of an online updated reference model of the air vehicle, then reconfigures for the change in real time. In addition, several nonlinear six degrees-of-freedom flight simulations on the certain type of folding-wing air vehicles have validate the effectiveness and robustness of the designed flight controller under the circumstances of sever change of aerodynamic characteristic and unknown atomospheric disturbances.