Experimental Study On Flexible Wings Deformation And Aerodynamic Characteristics Of Micro Flapping Wings

Flapping wing micro air vehicle is a new type of bird-like or insect-like aircraft that combines thrust and lift force in a flapping system.It has the excellence of high maneuverability,low energy consumption and low noise,thus making it extensive application prospects in the fields of reconnaissance and surveying.Flexibility of wings is an important feature of birds and insects,a large number of studies have shown that wing flexibility has an important impact on flapping flight performance,but the influence of many factors such as flexible wing structure,flapping trajectory parameters and wing deformation parameters on the mechanism of the aerodynamic characteristics are not fully understood.In this paper,the aerodynamic characteristics of the flexible flapping wing during hovering flight are studied by means of experimental measurement.The purpose is to explore the measuremen t method of wings deformation parameters,flexible wings aerodynamic characteristics and the influence of asymmetric flapping on the aerodynamic characteristics,which will provide data reference and control strategies for the design of the bionic flapping wing micro air vehicle.A prototype of bionic flapping wing micro air vehicle for experiment was developed,and the kinematics simulation analysis of the prototype was completed by using Matlab software.The RealSense depth camera was used to construct the three-dimensional shape measurement platform of the flapping wing.The wings dynamic three-dimensional shape of the experimental prototype in hovering flight was reconstructed,and the flapping parameters and maximum camber value of the wing were measured.The deformation process of different flexible wings were analysed and compared.The results show that the wings with less stiffness have irregularly adaptive deformation during flapping,resulting in large arch deformation.A flapping wing micro air vehicle aerodynamic measurement experimental platform was built.The effects of wings flexibility,flapping frequency and different up and down flapping angle combinations on the aerodynamic force and moments of the experimental prototype in hovering flight were studied.Four flexible wings with the same structural dimensions but different materials were designed,and the rocker was improved to achieve a time-asymmetry flapping of six kinds of up and down flapping angles under a constant maximum flapping angle.The experimental results show that the wings flexibility will affect the magnitude of the lift force,wings flexiblity have less influence on the thrust value,but it will affect the direction of the thrust.Flexible wing is easier to maintain its balance and stability during the flapping process,and the flexible deformation of the wings will make the aircraft a certain stability and adaptability.Different combination of up and down flapping angles will affect the lift force.Lateral force is mainly related to flapping mode and symmetry of experimental prototype structure,and asymmetric flapping has less influence on it.The work of this paper provides a new idea for studying the flexible deformation and flapping parameter measurement of flapping wing air vehicle.The relevant experimental results can provide guidance for the design and optimization of the flapping wing air vehicle.