Structure Design And Simulation Analysis Of Two-stage Bionic Flapping Wing Aircraft

A flapping wing aircraft is an intelligent robot that relies on flapping wings to generate aerodynamic forces.Because of its flexible maneuverability and strong concealment,flapping wing aircraft has a wide range of applications in military and civilian fields.The wings of existing flapping-wing aircraft are mostly single-segmented.Although this type of aircraft is relatively simple to process,it has poor aerodynamics and bionicity.In order to improve these problems,this subject has developed a two-stage flapping wing aircraft with foldable and flexible wings.The specific research contents are as follows:The main physiological structures such as bones,wings and feathers of large birds are analyzed,the posture changes of the wings and stress of birds in flight state are comprehensively analyzed,and the mechanism that birds can generate high lift is summarized.According to the scale law formula of flying creatures,the structural parameters such as the full-wing span,wing load and aspect ratio of the flapping wing prototype are calculated.Completed the overall scheme design of the prototype,specifically including the drive scheme design,flapping wing scheme design and tail wing scheme design.A two-stage flapping wing mechanism and a scissor-type V-tail mechanism are designed.The kinematic equation of the flapping wing mechanism is established,and the optimal solution of each rod length in the mechanism is solved using MATLAB software.In order to further verify the rationality of the flapping wing mechanism and the tail wing mechanism,based on the ADAMS software,the virtual flapping wing prototype model was dynamically simulated,and the motion characteristic curves of each member in the mechanism were obtained.Based on ANSYS software,the finite element static analysis was carried out on the easily damaged components(gear reduction unit,inner wing rod,outer wing rod)to ensure that the strength and rigidity of these components meet the design requirements.In order to study the aerodynamic characteristics of the prototype wing flapping,the CFD analysis software Fluent was used to numerically calculate the two-dimensional wing with an elliptical chord cross section,and the pressure cloud,lift and drag coefficients during the movement of the wing were obtained.curve.It can be seen from the simulation results that the bionic wing flap has a delayed shedding effectand a wake catching mechanism during the flapping process,which fully complies with the flapping wing movement law.Finally,through the steps of component selection,process design and processing and assembly,the production of the flapping wing prototype was completed.To further test the flight performance of the prototype,an outdoor flight test experiment was carried out on the prototype.The test results show that the aerodynamic performance of the two-segment flapping wing aircraft is more superior than that of the single-segment flapping wing aircraft,and its flying action is closer to that of real birds.