Research On The Kinematic And Aerodynamic Characteristics Of The Rigid-Flexible Coupling Spatial Flapping Wing Mechanism

Flying creatures have become the object that researchers of MAV(micro air vehicle)try to imitate,for their superiority such as small size,long range,high efficiency and high maneuverability.Because the flying posture of flying creature is full of variety and the flapping wing movement is exquisite and complex,the key point of bionic design is to imitate the flapping wing movement.As the core part of flapping wing movement,flapping wing driving mechanism plays an important role in the research of bionic flapping wing MAV.Based on the single crank double rocker flapping wing drive mechanism,a rigid-flexible coupling plane flapping wing drive mechanism was proposed in this paper for the problem of asymmetry of the left and right wing wings.,and put forward an improved scheme of rigid-flexible coupling spatial flapping-wing drive mechanism according to the analysis.After analyzing the motion characteristics of the mechanism without aerodynamic forces and the aerodynamic characteristics of the flutter-torsion-swing coupled motion,a coupled iterative analysis method for the flapping motion-aerodynamic characteristics was proposed.It was verified that the kinematic and aerodynamic characteristics of the mechanism meet the overall design requirementsThe main research work and conclusions are as follows:1.Aiming at the problems of asymmetric wing movement and low bionic degree existing in the flapping wing drive mechanism,the design requirements are put forward.Based on the single crank and double rocker drive mechanism,the rigid-flexible coupling planar flapping wing drive mechanism is designed.2.A virtual prototype model of rigid-flexible coupling planar flapping wing driving mechanism is established.According to the analysis results and design requirements,an improved scheme,rigid and flexible coupling spatial flapping wing drive mechanism,was proposed,which is able to achieve complex spatial coupling motion with lightweight mechanism.3.The Angle changes of the left and right wings of the rigid-flexible coupling spatial flapping wing driving mechanism,wing movement posture and wing tip trajectory,and the strength of the flexible rod structure are analyzed.From the conclusion,it can be concluded that the mechanism has stable periodic movement,the left and right wings have symmetry,and the trajectory of the wing tip is close to the "8"-shaped trajectory of the flying creature,with a high degree of bionics.According to the empirical formula,the aerodynamic force is estimated,and the tip trajectory of the wing is analyzed with or without aerodynamic load,and it is found that the aerodynamic force and the wing movement influence each other.4.By using Fluent,the UDF function,through the dynamic grid technology,the aerodynamic characteristics analysis model of the wing under the flapping-torsion-swinging triangular coupling motion trajectory was established.The correctness and validity of the analysis method are verified by three methods: grid density independence,time step independence and comparison.And analyzed the eddy current changes on the wing surface and the change in the lift-drag coefficient.5.The data exchange between Adams and Fluent was realized through MATLAB,and the coupling iterative analysis method of flapping wing movement-aerodynamic characteristics was proposed.The wing movement characteristics and aerodynamic characteristics under the influence of aerodynamic force were analyzed,and it was verified that the rigid-flexible coupling spatial flapping wing drive mechanism can satisfy the design requirements.