Research On Flight Control Strategy Of The Novel Ducted UAV

The variable ducted fan UAV is a kind of VTOL UAV with double fan configuration, which hasfeatures of both high-speed and low-speed flight performance. This innovational UAV has the specialability of autonomous navigation, and it can contribute more to military and civil applications,especially to the improvement of scientific researches.This thesis, firstly based on the low-speed configuration, studies its aerodynamic model andflight control technology. Then the flight control system is designed, by simulating and testing itsflight control laws, its validity and effectiveness are verified. This special UAV lays theoretical andpractical basis for the future researches and development.To begin with, mathematical model and stability of UAV is analyzed in this thesis, and then itsstructure and layout characteristics are discussed. Based on principles of aerodynamics and kinematics,the nonlinear model of this UAV is established, thus the linear model can acquire with the help of themethod of small perturbation linearization. Through the analysis of wind tunnel data, theseaerodynamic derivatives, stable and coupling characteristics are used as the theoretical basis; and thenflight control laws of this UAV can be proposed.Moreover, the flight control strategy is studied in the next chapter of this thesis. In this part, thesecontrol loops, including decoupling, augmentation, attitude, heading velocity, position and height, aredesigned. After that, these laws are verified by simulation. By means of these control loops, fixedpoint hovering, straight forwarding and coordinated turning modes are stated, combined withautonomous navigation mode, it successfully resolves the mode switch during the trajectory control.Besides, due to the uncertainty of these aerodynamic parameters of UAV, a kind of dual modeland strong tracking of adaptive controller is proposed. This controller is capable of separating modelstrong tracking and adaptive parameters, which meets these requirements of system stability marginand model tracking error during parameters adjusting. By simulating, this method is valid.Finally, the actual flight control system is designed and achieved in the last part of this thesis. Inorder to satisfy these needs of hardware resources, as well as the configuration of the flight controlcomputer, better sensors, actuators and wireless communication devices are selected and synthesized.Furthermore, ground station and onboard flight control software are programmed and tested.