Design And Experimental Study Of Two-Stage Flexible Flapping Wing Air Vehicle

The bionic flapping wing is an aircraft that simulates natural creatures such as birds,bats and insects.In view of the significant advantages of flapping wings relative to rotors and fixed wings,flapping aircraft application in many emerging fields.At present,the research on flapping-wing aircraft often ignores the torsional movement of the inner wing when the big bird is flying,resulting in poor general aerodynamic performance of the prototype.Aiming at this situation,this paper designs a two-stage bird-like flexible flapping wing aircraft,which can carry out two degrees of freedom movement in the span direction and the inner and outer chords,design and manufacture the flapping wing prototype,and carry out corresponding experimental research.In order to design a flapping wing aircraft with excellent bionic performance,this paper studies the flight mechanism of large birds such as seagulls,analyzes the wing structure of large birds and the movement and stress of birds during flight,and clarifies the design requirements.The mathematical relationship between the flight parameters of birds was established.On this basis,the overall design scheme of the prototype is proposed,including flapping scheme,transmission scheme and tail fin scheme.Since the core motion of the bionic flapping wing aircraft is realized by its flapping mechanism,the flapping mechanism is dimensioned.The mechanism kinematics equation is established to analyze the angular,velocity and acceleration of the flapping mechanism.Estimate the aerodynamic force of the flapping machine using the strip theory.The three-dimensional modeling of the flapping mechanism is carried out,and the dynamics simulation analysis is carried out to obtain the force of each hinge point of the flapping mechanism to ensure the structural strength of the mechanism.Based on the size design of the flapping mechanism,the overall structural design of the flapping wing prototype is performed,and the prototype is processed.Based on the determination of the fluttering scheme,the detailed structural design of the flapping mechanism,including the connection between the inner and outer wings,etc.;the detailed structural design of the inner and outer wing torsion mechanism,airfoil and tail fin of the flapping wing prototype;The appropriate materials for each component are selected for part processing,and the flapping machine is assembled.In order to obtain the aerodynamic characteristics of the designed flapping machine,a specific experimental scheme was designed to perform the aerodynamic test of the prototype.According to the previously estimated aerodynamic and dynamic simulation analysis,select the appropriate range of sensors and design the corresponding experimental platform;Under different conditions,the aerodynamic data generated by the two-stage bird-like flexible flapping wing prototype was collected,and the change trend of the lift thrust with the change of conditions was analyzed.The effect of inner wing torsion on the aerodynamic performance of the prototype was compared.