Design And Control Of A Tilt Tri-rotor Flying-Wing UAV System

Tilt-rotor UAV,as a hybrid aircraft,can not only cruise at high speed like fixed-wing UAV,but also have the ability of vertical take-off and landing and fixed-point hover of rotor UAV,so it has a wide application prospect.Compared with the tilt quadrotor,the tilt tri-rotor UAV has higher efficiency and more compact configuration.However,due to its asymmetric power configuration,the system coupling is stronger and the control is more difficult.In order to reduce the control difficulty of tilt tri-rotor UAV in the process of vertical take-off and landing,researchers use tilting coaxial twin rotors or tail-single rotor roll-over power unit configuration.However,such a design resulted in part of the power unit becoming an ineffective load during cruise,reducing the payload of the UAV.In order to solve this problem,this dissertation designs a tilt tri-rotor flying-wing UAV system different from the above configuration,three rotors configured around the fuselage can be longitudinal tilting through a certain mechanical structure.This configuration gives the UAV the ability to hover at a non-zero pitch angle in the process of vertical take-off and landing,but at the same time,it increases the difficulty of control.At present,there are still few researches on this aspect.Therefore,this dissertation studies the position and attitude control of UAV in Rotor Mode,and the main work is divided into the following three aspects:1.The specific configuration description of the object is given,the basic design principle,different flight modes and their transition process are introduced,and the classical Newton-Euler method is used to model the kinematics and dynamics of the UAV.According to its dynamic configuration,the force and moment models are given.2.In order to solve the problem that the UAV is susceptible to crosswind distur-bance at large elevation angle,and the attitude representation of Euler Angle appears singularity at this time,this dissertation proposed a linear active disturbance rejection control algorithm based on unit quaternion attitude representation,and designed a P-PID position control algorithm which is different from traditional position-attitude control framework and a control allocation strategy in arbitrary elevation angle.3.In order to verify the effectiveness of the relevant control algorithm,a simulation model was built in the MATLAB/Simulink environment,and the simulation analysis was carried out.At the same time,a small testing machine system is designed and made,and the effectiveness of the relevant algorithm on the real flight control system is verified through outdoor flight test.