Multibody Dynamic Modeling And Control Of A Folding Wing Aircraft

Morphing aircraft are conceived as multirole platforms that modify their external shapesubstantially to adapt to a changing mission environment. The folding wing concept developed byLockheed Martin Aeronautics Company divide each wing into two parts, and they are folded by fouractuators placed in the wing junctions.The folding wing aircraft is a variable geometry multi-body system which composed by innerwings, outer wings and the fuselage. When the wings are folding, the aspect ratio, moments of inertia,wing area, locations of aerodynamic center and center of gravity alter considerably. Here, theaerodynamic coefficients are calculated by DATCOM with quasi-steady supposition. The flightstability and maneuverability during the whole morphing process are analyzed by uncertainaerodynamics. Variation laws of aerodynamics with folding angle and angle of attack are found, thenthe fitting functions are obtained by using Matlab curve fitting tool.The system of folding wing is modelled on multi-body dynamics theory and kinematics principle,and the longitudinal linear differential equations are obtained by using decoupling method andlinearization technologies. The dynamic response of folding wing aircraft without control during thewhole flight indicates that the aircraft loses altitude significantly and bonces up and down in longperiod.The affine parameter dependent LPV model with uncertain time varying parameter is reduced toPloytope by using convex decomposition algorithm. The gain self-scheduled H-infinity robust statefeedback controller is designed by affine parameter dependent Lyapunov function method. Theclosed-loop simulation results prove the feasibility and efficiency of this method. The aircraft turns ina good dynamic performance during the whole wing shape transition process and then sets down to asteady state quickly.The3D model of folding wing aircraft is built to improve visibility and interactivity. The modelis induced into the virtual reality toolbox and connected to the system model. The integratedsimulation not only gives the results and curves but also the flight trajectory and posture changeduring the whole flight. This method can increase comprehension of the model and accelerate designand test process effectively.