Design,Control And Flight Tests For A Vertical Take-off And Landing Fixed Wing Unmanned Aerial Vehicle

In order to reduce the dependence of the aircraft on the runway,reduce the cost and carry out diversified missions,researchers in the aviation field are paying more and more attention to the application of the vertical takeoff and landing(VTOL)technology in unmanned aerial vehicle(UAV).This paper is intended to design a small UAV that has the advantages both of stable function of VTOL and long-endurance,far distance of fixed wing.Although this VTOL fixed-wing UAV uses relatively mature form of multi-rotor and fixed-wing aircraft,the combination of these two still has difficulties in design,such as the choice of composite layout,the aerodynamic interference between the rotor and the fixed-wing,new requirements for structural design caused by two power systems,the stability of two flight modes and their switching process,and so on.In this paper,the above key points are respectively targeted at different stages of design.The overall design plan is reached after all the general parameters being discussed in detail from the preliminary analysis to detailed design;The aerodynamic characteristics of the UAV during the flight of fixed-wing mode and the aerodynamic interference between rotor downwash flow and fixed-wing airfoil in three conditions: vertical take-off and landing,hovering and forward flight,are emphatically analyzed;Then,the aerodynamic parameters are used to calculate main flight performances to verify the rationality of the design;Using the modular design thinking and new composite materials for structure optimization design;Classic PID control method is used respectively to three flight patterns,in which to maintain the stability of the switching process,a unique control scheme was put forward.In the end,a complete prototype was assembled and the feasibility of design was verified through flight test,which provided an important reference for the further study on the VTOL fixed-wing UAV.