Structure Design Of Double-engine Variable-pitch Quadrotor UAV

The quadrotor Unmanned Aerial Vehicle(UAV)develops rapidly in recent years,which has such advantages as vertical take-off and landing,fixed-point hovering,flexible maneuvering and easy operation.Highly accepted by the market and consumers,quadrotor UAV is the hottest products in the drone market.Because of small payload and small flight radius of the traditional electric quadrotor UAV,this paper mainly designed a double-engine variable-pitch quadrotor UAV,which effectively increased the flight time and payload.Firstly,this paper introduces the development of multi-rotor UAVs domestic and abroad,pointing out the shortcomings of electric multi-rotor UAVs,and comprehensively compares the advantages and disadvantages of various oil-powered multi-rotor UAVs.Secondly,according to the design requirements,the overall parameters of the drone and the unique structure layout were determined.The three-dimensional geometric model was established.The flight principle of the variable-pitch quadrotor was clarified.Then,according to the basic requirements of aircraft structural design,this paper designed two different types of fuselage structures and analyzed the strength and stiffness characteristics of the fuselage through finite element analysis method.Considering various factors such as weight,cost and manufacturing,this paper choose one more suitable fuselage.The free vibration model without damping is established to solve the natural frequency and vibration mode of the fuselage,verifying the vibration characteristics of the fuselage by comparing with the excitation frequency of the rotor and engine in order to avoid resonance theoretically.Then,according to the requirements of the landing gear design,the basic form of the drone landing gear was determined.The finite element model was established and the static strength was calculated under various working conditions.The landing impact analysis was carried out to obtain the stress and strain,And results showed that the design meets the requirements.Finally,This paper successfully assembled the UAV,and the flight test results showed that the structural design of the UAV meet the requirements.