Design Of Tilting Device And Research On Transition Section Of Tilting Wing UAV

Aiming at the problem that the downwash flow of the rotor is blocked by the wing and the aerodynamic efficiency of the rotor is reduced in the vertical take-off and landing mode of the tilting rotor aircraft,the tilting wing UAV is designed.In order to solve the transmission and control problems of the tilting process of the tilting wing aircraft,this paper has carried out a lot of analysis work on the design of the tilting mechanism in combination with the disciplines of structure and aerodynamics.main tasks as follows:1.According to the real model of the tilting wing UAV,the 3D model of the UAV is built in the CATIA modeling software,and the grid of the UAV calculation flow field is generated in the grid module of the ANSYS Workbench software.2.In order to achieve the requirements of the UAV with a fixed height during the tilting process,this paper uses the momentum source method to simulate the effect of the rotor on the flow field,combined with computational fluid dynamics(CFD)and traditional dynamics numerical calculation methods,using the slip mesh method caculates the unsteady state of the UAV tilting process in the transition,then,the corridor curves of transition time in relation to the angle of attack of tilting wing,forward flight speed and rotor tension in the transition section are fitted,it is provided the basis for UAV fixed flight control.3.According to the force characteristics of the transition section of the tilting wing aircraft,a tilting device capable of meeting the conversion flight mode of the tilting wing UAV is designed.The device is made of the composite named POM with low density and simulated the transient dynamics in the Workbench,analyzing whether the allowable stress of the material can meet the requirements of the device.After comparison and analysis,the results show that the efficiency of the rotor gradually decreases with the change of the angle of attack of the tilting wing during the transition from the hoisting mode to the leveling mode;by fitting the transitional corridor curve of the tilting wing UAV,the design difficulty of the fixed height flight control system is greatly reduced;the tilting device designed in this paper can meet the design requirements,the contact stress of the worm and wormwheel is much smaller than the allowable stress of the material,and meets the strength requirements of the device,after the stress cycle is 10~7 times,The strength of the material can still meet the requirements,indicating that the life of the device used in this type of force is theoretically close to infinity and can be used permanently.