Research On Design And Key Technology Of Flapping-wing Aircraft

With the rapid development of artificial intelligence,self-driving,Internet of things,industrial big data and other fields,it is promoting the social change.The rapid development and maturity of four-axis rotor UAV proves that people's demand for aircraft is also an important part of this trend of science and technology.Although flapping wing flight is the perfect flight mode after natural selection,due to the immaturity of theoretical research,material limitation,insufficient technology and the late appearance of micro-electro-mechanical system,the research on flapping wing aircraft has been carried out relatively late.However,flapping-wing aircraft with the advantages of high maneuverability,high degree of miniaturization,good concealment,high speed,long voyage,safer human-computer interaction and other advantages,has been called the most promising aircraft by many aviation scientists.On the basis of fully studying the flight mechanism,dynamics and kinematics model of flapping-wing aircraft,this paper designs and improves the flapping mechanism,attitude control and path planning of flapping-wing aircraft by combining the existing classical methods.Aiming at the problem of poor flexibility caused by symmetrical synchronous flapping mechanism commonly used on both wings of flapping-wing aircraft,a single motor and double hinges drive are adopted to design the frequency conversion mechanism,which realizes an asynchronous frequency conversion flapping mechanism.The left and right wings can independently adjust or correct the flapping frequency to realize flexible maneuvering flight.Secondly,in view of the attitude regulation and nonlinear system characteristics of flapping-wing aircraft in hover,sliding mode control is introduced in this paper.First,the traditional sliding mode control law is simulated and realized.It is found that the response speed is slow and the delay is certain.Secondly,the hyperbolic tangent function is introduced to adjust the flapping wing attitude control.Aiming at the influence of uncertain disturbances in the system,attitude control design is carried out based on robust inversion sliding mode and adaptive inversion sliding mode,respectively.The results show that the response is fast and the disturbances can be eliminated.Finally,considering the non-linearity of flapping-wing aircraft and the chattering phenomenon of sliding mode control,a double closed-loop sliding mode control is adopted to realize the attitude adjustment of flapping-wing aircraft.The inner and outer loops are designed to adjust theattitude angle and driving angular velocity respectively,and finally the attitude control is achieved.The simulation results show that the control method has fast and stable response.Aiming at the randomness of searching extended nodes in flight path planning algorithms such as A* algorithm and artificial fish swarm,which results in large computation and low efficiency,such as the poor real-time performance of A* algorithm in local planning,a three-dimensional space environment model based on aperture is designed.On this basis,the concept of obstacle function is introduced,and an obstacle function-based model is designed.Local route planning method and global route planning based on improved A*algorithm can avoid obstacles accurately and save a lot of search space.The innovation of this project is to design an asynchronous frequency conversion flutter mechanism,which can realize the independent FM of left and right wings.Secondly,four attitude control methods based on hyperbolic tangent function sliding mode control,robust inversion sliding mode control,adaptive inversion sliding mode control and internal and external double closed-loop sliding mode control are designed respectively.Aiming at the trajectory planning environment,a three-dimensional space environment model based on aperture is designed.Finally,a local trajectory planning method based on obstacle function and a global trajectory planning method based on improved A* algorithm are designed respectively.