折叠翼飞行器设计与气动仿真分析

Design and aerodynamic simulation analysis of folding wing aerial vehicle

为提高扑翼飞行器的气动效率,分析自然界鸟类翅膀运动机理,设计拍打-折叠运动的仿鸟飞行器机构,实现了仿鸟翅膀“8”字型运动轨迹。区别于传统扑翼飞行器的膜状翼结构,模仿鸟类翅膀羽毛分层结构,研制出羽毛机翼。利用计算流体力学仿真软件XFlow,研究机翼初始迎角,展弦比和扑动频率对折叠翼扑翼飞行器的气动特性影响。实验结果表明:机翼初始迎角在5°时取得最大升阻比系数,有利于飞行器快速升空及平飞飞行;扑动频率在4~5 Hz时获得最佳气动效率;机翼展弦比为3,扑翼飞行器获得较优气动性能。羽翼动力折叠翼飞行器成功飞行,为研制机翼多自由度变形仿生机器鸟提供理论上的可行性和有效飞行平台。

To improve the aerodynamic efficiency of flapping-wing aerial vehicles,the mechanism of natural bird wing motion was analyzed,and a bird-inspired mechanism utilizing a flapping-folding motion was designed to mimic the“8”trajectory of bird wings.Being different from the membrane wings of legacy flapping-wing aerial vehicles,a feather wing was developed by imitating the layered structure of bird wing feathers.The effects of the initial wing angle,aspect ratio and flutter frequency on the aerodynamic characteristics of the wing were determined using XFlow computational fluid dynamics simulation software.The results show that at an initial wing angle of 5°,the maximum lift-drag ratio was achieved for rapid lift-off and level flight.The best aerodynamic efficiency was obtained at a flutter frequency in the range of 4~5 Hz.Better aerodynamic performance was obtained with a wing aspect ratio of 3.The successful flight of the man-made feathered wing-powered aerial vehicle can provide theoretical feasibility and an effective flight platform for the development of a multi-degree-of-freedom deformation bionic robotic bird.