Design Of Crane-Like Flapping-wing System And Research On Its Areodynamic Performance

Foldable flapping-wing air vehicle belongs to the category of bionic flapping-wing aircraft.Flapping-wing aircraft,unlike conventional fixed-wing aircraft or rotorcraft,is a new concept of aircraft which generates lift and thrust by wings flapping up and down,folding and twisting around the lever.Currently,flapping-wing aircraft has caused a wave of international research and the study on aerodynamics has made considerable progress.Based on this background,we propose a design of a foldable flapping-wing air vehicle and carry out continuous systematic research on the flight mechanism,the flapping-wing structure,the overall layout of the prototype and the aerodynamic performance.We study the structure and the motion characteristics of birds' wings in the flight from the perspective of bionics,especially the high-lift mechanism of white crane.It also come up with the design requirements for the structure and prototype accordingly.We propose a crane-like and foldable flapping-wing system.And we use SolidWorks to model,do kinematics simulation with ADAMS,and optimize the flapping-wing structure according to the equation of motion.We do numerical simulation of two-dimensional flapping-wing-type flow field with the methods based on computational fluid dynamics(CFD)for unsteady incompressible viscous airfoil flow field.The results that there is little difference between the calculation results from the rigid wing flow field with two degrees of freedom of swating and twisting to the flexible wing flow field with a single degree of freedom.And we also analysis the influence of six different airfoil to the lift and thrust characteristics in flapping-wing flight comparatively.The results show that the airfoil of S1223 with larger camber has a maximum lift coefficient and a moderate thrust coefficient,suitable as the second wing of the prototype;Another airfoil,named 2032 cjc,with a large camber has a maximum thrust coefficient and the lift coefficient is moderate,which is suitable as the first wing of the prototype.Beased on the previous studies,we launch specifically and detailed design work for the prototype.We produce a crane-like and foldable flapping-wing system prototype with a wingspan of 2.0 meter,and total weight of 575.5g.And we design the lift and thrust testing experiment.The result show that each design for prototype is feasible and our work lay the foundation for further research.