Design And Experimental Research Of The Folding Wing Imitating The Hind Wing Of Allomyrina Dichotoma

Micro Air Vehicle(MAV),imitating birds,bats or insects,is a kind of aircraft,and it has the advantages of small size,strong maneuverability and easy concealment.However,the wings are easily damaged in the process of transportation and carrying.If the MAV has a wing structure which likes folding wing,there is no doubt that it can play a very good role in protecting the wings of flapping-wing air vehicle,and it also plays a key role in the carrying and storage of flapping wing air vehicle.Therefore,the research of foldable wing has gradually become a hot spot in the industry.The hind wings of Allomyrina dichotoma(Coleoptera)are unfolding when they fly,and keep folding when rest.Inspired by the characteristic,this paper studies and designs a folding wing prototype which can imitates the folding and unfolding movement of the wings of insect.Through the experimental test and analysis of deployment performance of the wing,the research provides good ideas for the following-up research of folding wing air vehicle.Firstly,from the perspective of bionics,the Allomyrina dichotoma(Coleoptera)is taken as the research object.A high-speed camera system is built to capture the folding and unfolding process of the Allomyrina dichotoma,and the behavior characteristics of the hind wings are analyzed during folding and unfolding movement.Scanning electron microscope(SEM)and confocal laser scanning microscope(CLSM)are used to observe the vein of hind wings of the Allomyrina dichotoma.The microstructure and the distribution of resilin in the bending part of the hind wing are studied.It is found that where the wrinkle structure in the Bending zone and Marginal joint of the hind wing and the bending part of the vein are there more resilin.To study the mechanism of the resilin,a numerical simulation by using the ANSYS of finite element analysis software has been conducted,and the results show that the stress distribution can be changed by the wrinkle structure and resilin of the vein can improve the mechanical properties of the veins.Secondly,referring to the crease form of the hind wings of Allomyrina dichotoma,the rigid origami model theory is used to design the wing of the folding wing air vehicle.By the SEM and CLSM observation results the elastic joint is designed,and it is made by Ni Ti alloy wire and machining method.Using the 3D printing technology to made the driving mechanism,and the whole assembly of the folding wing prototype is completedFinally,according to the experimental requirements,the deployment performance of the folding wing prototype is studied by the test platform which is made up of the high-speed camera and three-dimensional force sensor.By observing the deployment and trajectory of the prototype wings and comparing the lift characteristics of rigid flapping wing,flexible flapping wing and flexible folding wing,which found that the wing deployment characteristics of the prototype fit the expected design.The folding wing can improve the average lift and enhance the aerodynamic performance.