Design Research And Optimization Of Raptor Flapping Wing Aircraft

The Raptor ornithopter is a kind of aircraft that imitates the body structure of the Raptor and generates lift by flapping wings.Compared with fixed wing and rotary wing aircraft,it has better flexibility,and can be used in situations where fixed wing and rotary wing aircraft are not competent.Common ornithopter aircraft include ornithopter to drive UAVs,early warning ornithopter,self destructing ornithopter,reconnaissance ornithopter,underwater ejection ornithopter,etc.The existing research on bionic ornithopter mostly focuses on the mechanism design and aerodynamic analysis,and there are few related vibration analysis and structural optimization design;Due to its high precision image processing capability,the mechanical vibration of the Raptor ornithopter needs to be analyzed in depth.In view of the above background,the paper uses the bionic rate formula to theoretically design the ornithopter prototype,and uses SOLIDWORKS to make the prototype assembly model.Based on this model,ANSYS is used to simulate the transient dynamics of the bearing supporting the shaft at the model reducer,the spatial crank rocker mechanism,and the reducer gear pair,which shows the rationality of the design from the numerical point of view.At the same time,for the sake of safety,Improvements have been made to the ball head bolt structure;The wing skeleton is designed with stiffeners,and its stress is simulated with statics module.The results show that the stress of the wing skeleton is greatly reduced after adding stiffeners;The first six vibration modes and natural frequencies of the spatial crank rocker mechanism,reducer gear pair,Deep Groove Ball Bearing and the wing skeleton without improvement and improvement are obtained through modal analysis.It is simulated that the above structures will not resonate under the action of the motor excitation source;Then,through harmonic response analysis,it is determined that the displacement response values of the Ctype wing under a certain amplitude of harmonic force are smaller than those of the A-type and B-type wings,making it more suitable as the wing skeleton of the prototype;The influence of the number of sides of regular polygon on the modal of the wing skeleton is investigated when the section shape of the wing skeleton is regular polygon;The study also conducted size optimization based on modal analysis on the parts of the tail wing that are prone to resonance,and the optimized first order frequency of the tail wing skeleton has been improved;Due to the potential danger caused by the sharp edges of hand torn steel,low-frequency flapping was tested,and the experiment showed that the average flapping frequency under low-frequency flapping was3.43Hz;During the flapping process,the prototype produced a slight tilt back,mainly due to the center of gravity being offset from the prototype.Multiple sets of bird heads were carved and installed on the front end of the prototype through precision carving of Surfmill 8.0 for head to body weight ratio testing,which initially alleviated the tilt back problem.