Design And Experimental Study Of Passive Deformation Flexible Flapping Wing Air Vehicle

Bionic flapping-wing aircraft is an aircraft that imitates flying creatures such as birds,insects and other flying creatures using flapping wings to complete flight.Because of its flexibility and high aerodynamic performance,it has a wide range of application prospects.At present,most large bird-like flapping-wing aircraft with better flying effects are single-segment wing structures,which cannot achieve folding and deformation functions.In order to better simulate the flight movements of birds,many organizations have conducted research on flexible wings.Based on the flapping movements of birds during the flight,this paper designs a two-stage passively deformed flexible wing bird-like flapping-wing aircraft,which can achieve passive deformation during the flapping process of birds and improve flight lift.Based on this aircraft,the effects of flapping frequency and wing stiffness on lift were tested.In order to better simulate the flight movements of birds,the structure and shape of bird wings and the flapping laws during flight were analyzed.The design requirements of the passive deformation mechanism and wing shape are determined according to the flight laws of birds and the wing shape of large birds.According to the dimensional relationship between the bird’s body shape and body weight,the flight parameters of the bird’s flight are determined.On this basis,the design of the driving plan,the flapping plan,the wing structure plan and the tail plan are determined.In order to be able to carry out theoretical analysis and aerodynamic estimation of the flapping mechanism,the flapping mechanism was first modeled according to the preliminary determined flight parameters.According to the geometric relationship of the flapping mechanism,the flapping angle,angular velocity and angular acceleration of the inner wing of the wing are calculated.According to the deformation characteristics of passive deformed wings,a mathematical model of the deformation mechanism is established,and on this basis,the aerodynamic force of bird wings is estimated.The influence of the deformation node position and folding angle of the flexible wing on the lift of the prototype is analyzed.The calculation results show that the closer the node is to the wing root and the larger the folding angle,the more beneficial it is for the lift of the aircraft.After determining the size of the flapping mechanism and the shape of the wings,the rest of the bird needs to be designed and processed in detail.Completed the selection of drive motor and the design and assembly of deceleration mechanism,airfoil skeleton design,passive deformation mechanism design and tail wing mechanism design.The selection of each executive element and control system was determined,appropriate materials and processing methods were selected for the completed design plan,and the prototype assembly was completed.The test plan was selected based on the existing force measurement platform in the laboratory,the data acquisition card was selected to complete the construction of the force measurement platform and the fixed plan of the prototype,and the force measurement platform was debugged.A force measurement experiment was carried out on the designed prototype: the effect of flexible wings with different stiffness on the lift of the prototype,the influence of flexible wings with different flapping frequencies on the lift of the prototype,and the lift performance of the rigid wing and the flexible wing.Experiments show that the flexible wing improves the lift efficiency,and there is a connection between the flapping frequency of the flapping wing prototype and the rigidity of the flexible wing.