Envelope Protection Reconfiguration for Iced Aircraft

Ice accretion is an important factor that affects the flight safety of civil aircraft, and reconfiguration of the envelop protection control is an important way to improve the iced aircraft flight safety. However, in the present studies, the icing dynamic model utilized the constant coefficient ice factors, which may not accurately reflect the aerodynamic characteristics of iced aircraft in the larger angle-of-attack range. Therefore, in this work, based on the wind tunnel data, a more accurate nonlinear icing aerodynamic model is established which uses the variable coefficient ice factors. Moreover, the reconfiguration method of the envelope protection parameters is given. Three feasible reconfiguration methods of the protection boundary of the angle-of-attack are discussed, and the control is designed respectively. Finally, through the simulation under the icing environment, the differences between the proposed schemes are analyzed, and the results show that the selected scheme can improve the flight safety of the iced aircraft more effectively.