Research on Gust Response Alleviation of an Elastic Aircraft
LIU Cheng-cheng;ZHAO Yong-hui;State Key Laboratory of Mechanics and Control of Mechanical Structures,Nanjing University of Aeronautics and Astronautics;
The overloads induced by discrete gust and continuous turbulences can be efficiently suppressed by introducing the gust load alleviation system. For a civil airplane,firstly,based on the structural dynamic equations and the unsteady aerodynamics model,the open- loop aeroelastic equations of an elastic airplane under gust input and the deflection of the control surfaces are established. Secondly,by introducing the coordinate transformation,the relationship between the rigid body modal coordinates and the motion variables defined in flight dynamics is obtained,which results in the integration equations in aeroelasticity and flight dynamics. Besides,the ailerons and the elevators are used as control surfaces to alleviate the gust responses. For continuous and discrete gusts,the corresponding control laws are designed,in which the pitching rate,acceleration in wing tip and mass center are used as the feedback signals. The simulation results show that the control system can effectively alleviate the wing- tip overloads and the bending moments at the wing root.