Design And Dry-fly Motion Control For Bionic Folding Tilt Tri-rotor UAV

As a new type of UAV,the bionic folding tilt tri-rotor UAV has the advantages of fixed wing and multi-rotor.It can realize the functions of crossing medie:entering water and jumping out of water.Quickly reaching the target area to perform tasks has important application value in the military and civilian fields.In this paper,a bionic folding tilt tri-rotor UAV is designed.The dynamic model is established and model parameters are identified.The virtual quantity allocation algorithm in the helicopter mode is designed and simulated.The prototype of the UAV is tested in various modes and achieves the expected results.This article mainly carries out the following work:(1)On basis of characteristics of the bionic folding tilt tri-rotor UAV,the concept of tilting structure and the concept of folding wings are proposed which provide conditions for the UAV's water entry action.The theoretical calculations show that the design has smaller rotor/wing aerodynamic interference.The take-off weight is calculated and the theoretical verification of the power system is carried out which create conditions for the realization of the normal flight function.(2)The force analysis and dynamics modeling of the fixed-wing mode and multi-rotor mode of the dry-fly phase are carried out.The parameters in the model are experimentally identified.The tension coefficient and the torque coefficient,the moment of inertia of the UAV and the relation between control signal of tilting servo with the tilting angle are obtained.The open-loop model of the UAV is simulated,indicating that the flight control system is essential for the UAV.(3)For the control of the helicopter mode in the dry-fly phase,the control allocation is carried out.Based on the traditional distribution algorithm,the static control allocation method and the speed priority allocation method are obtained.For the angle control and the angular velocity control loop of the attitude control,the PID controller is designed.Based on the control quantity distribution algorithm and PID controller,the UAV control system is built in MATLAB/SIMULINK.The simulation results show that the speed priority allocation method shows better performance.(4)Based on the theoretical calculation results,the tilt tri-rotor UAV was built,and the Control electronic components and communication electronic components are selected.The UAV is debugged before the flight.After the UAV has the conditions required for flight,Fixed point hover test,interference test,fixed altitude flight test and fast forward flight test are carried out.The results under the tests in various modes show that the UAV can realize the attitude-stable flight mission.