基于蜻蜓翅几何及刚度相似性的仿生扑翼结构

A dragonfly-like flapping wing structure based on geometry and stiffness similarity

目前对于扑翼和扑旋翼飞行器的研究主要致力于实现仿生拍动模式的机构设计和气动特性分析,对昆虫翅的研究主要在微观尺度的生物学构成以及材料和力学特性。采用主成分分析法可建立昆虫翅展向抗弯刚度与几何形态参数之间的关系。以仿蜻蜓翅的扑翼设计为例,根据蜻蜓翅脉的分布可设计具有几何相似性的扑翼模型,进而基于蜻蜓翅的展向抗弯刚度实验结果建立仿蜻蜓翅扑翼设计的刚度相似性准则,以刚度相似性为约束对扑翼进行结构优化,分别制作了仅具有蜻蜓翅刚度相似性的矩形扑翼(JX-翼)、仅具有蜻蜓翅几何相似性的扑翼(JH-翼)、基于蜻蜓翅几何相似性和刚度相似性的仿生扑翼(GD-翼),并采用扑旋翼模型分别对这3种扑翼在5~15 Hz的拍动频率范围内进行了升力测试实验。结果表明,基于几何相似性及刚度相似性设计的GD-翼在12.5 Hz拍动频率时产生的升力比仅基于刚度相似性的矩形JX-翼提高25%,在低于6.5 Hz时与仅基于几何相似性设计的JH-翼相近,但在高于8 Hz时比JH-翼的升力大2倍以上。基于蜻蜓翅的几何相似性和刚度相似性的扑翼结构设计方法为提高仿生扑翼和扑旋翼的气动升力和效率提供了新的路径。

At present,the research on flapping wing and flapping wing rotor micro aerial vehicles is mainly focused on the flapping mechanism design and aerodynamic characteristics analysis.The research on insect wings is mainly fo-cused on the biological composition in micro scale,the material and mechanics.In the present study,the principal component analysis method is used to establish the relationship between the spanwise bending stifness and the geo-metric parameters of insect wings.Taking the dragonfly-like flapping wing design as an example,a bionic flapping wing of geometric similarity to the structure layout of a dragonfly wing was designed.In addition,a stiffness similarity criterion for the dragonfly-like flapping wing design was established based on the experimental results of the spanwise bending stiffness of the dragonfly wings.The flapping wing structure was then optimized by using the stiffness similarity criteria as a design constraint.Test samples of a flapping wing(JX-wing)of rectangular shape and only stiffness simi-larity to dragonfly wings,a flapping wing(JH-wing)with only geometric similarity to dragonfly wings and a flapping wing(GD-wing)of both geometric and stiffness similarity to dragonfly wings were manufactured.Aerodynamic lift forces of those flapping wings were measured in the flapping frequency range of 5-15 Hz based on a flapping wing ro-tor test platform.The test results show that the GD-wing of both geometric and stiffness similarity can generate 25%higher lift than the rectangular JX-wing of only stiffness similarity at 12.5 Hz flapping frequency.The lift produced by the GD-wing of both geometric and stiffness similarity is close to the JH-wing of only geometric similarity when the flap-ping frequency is below 6.5 Hz,but increased to at least twice larger than the JH-wing when the flapping frequency is above 8 Hz.The flapping wing structure design method based on both geometric similarity and stiffness similarity pro-vides a pass-way to improve the aerodynamic lift and efficiency of flapping wing and flapping wing rotor.