Structural Design And Test On A Flexible Flapping Wing Vehicle

Flapping-wing vehicle is a kind of aircraft that bionic birds or insects and has the characteristic of good stealth.It has broad prospects in the military and civil.At present,the research on flexible flapping-wing vehicle mainly focuses on the simulation numerical analysis.The generally used single-wing or two-wing form are difficult to simulate real birds.The wing’s flexibility is not obvious,and pneumatic is not good.In this paper,a new type of prototype which has flexible flapping wings is designed and relevant experimental tests are carried out.In view of the existing defects,the design for flexible flapping-wing vehicle is presented.The structure of the bird’s wings and the basic motions are analyzed.Based on the above analysis,the overall structure of the vehicle is designed.The wing adopts three four-bar linkage in series to realize the flexible feature.At the same time,parameters are determined according to the size rules of the birds.Based on the mechanism design,the motion equations are established,the mechanism parameters are designed and the mechanism is simulated.According to the movement parameters,the parameters of the flexible wing are determined,and the crank-rocker mechanism is optimized to ensure the transmission performance.According to the geometric relationship,the kinematics equation is built up,and we can intuitively analyze the angular velocity and acceleration characteristics.Above this,the motion model of the flexible wing is established,aerodynamic force is carried out by using the strip theory.The dynamics model is simulated to analyze the stress of each hinge point and guarantee the structural strength of the mechanism.The overall structure model of the prototype is designed,machined and assembled.We select the suitable driving motor and proper reduction gear ratio according to the result of dynamics simulation and the fluttering frequency of wings.The space four-bar linkage mechanism is proposed to realize the wings’ torsion action.By detecting the output voltage of the angle sensor,the steering gear and the incidence angle of the wing are real-time controlled.In order to obtain aerodynamic characteristics,a two-dimensional test platform is set up and prototypes are tested.The data acquisition and sensor calibration softwares are writed under Labview.According to the change of data under different conditions,the trends of lift and thrust of the flexible flapping-wing vehicle are analyzed.At the same time,the force is compared with the two-wing aircraft.