Research On Flight Dynamics Of Tilt Ducted Rotor Aircraft

The tilt ducted rotor aircraft is a new configuration aircraft with the ability of vertical take-off and landing and high speed forward flight.It is a new area of the current research and development of UAV.Flight dynamic modeling of the tilting ducted rotor was studied in this thesis.Firstly,the configuration of the tiling ducted rotor aircraft was studied in this thesis,which possesses advantages of both helicopters and fixed-wing aircrafts.According to the design requirements of the tilt ducted rotor aircraft,the overall parameters of the aircraft were determined,the 3D model of the aircraft was derived,and the flight performance of the aircraft was evaluated.Secondly,the factors affecting tilting ducted rotor aircraft were simulated through unstructured mesh technique.Through the numerical simulation of the fuselage,the force and moment coefficients of the fuselage under different angles of attack were obtained.Through the numerical simulation of the ducted rotor,the values of the thrust and power generated by the ducted rotor at different speeds were obtained.Through the analysis of the pressure and velocity cloud images obtained by CFD post-processing,the flow field characteristics around the fuselage and ducted rotor were obtained respectively.Thirdly,the nonlinear flight dynamics model was established.The rotor aerodynamic model was established by using the blade element theory.While the fuselage aerodynamic model is obtained with the aerodynamic coefficients calculated by CFD techniques.The landing gear model was simplified by a spring-damping system to evaluate the counter-force and friction force when it contacted the ground.Based on the mechanism modeling methodology,a 6-DoF nonlinear flight dynamics model of the aircraft was derived.Finally,a nonlinear simulation model was built under MATLAB/Simulink environment to calculate the hovering and forward flight states of the aircraft.According to the trimming results,the control strategy of the aircraft was obtained and the stability of the aircraft was analyzed.The coupling characteristics of each control channel were analyzed by calculating the nonlinear response of the aircraft.