Drawing inspiration from insect flapping wings, a Flapping Wing Rotor (FWR) has been developed for Micro Aerial Vehicle (MAV) applications. The FWR features unique active flapping and passive rotary kinematics of motion to achieve a high lift coefficient and flight efficiency. This study thoroughly investigates the aerodynamic performance and design of a bio-inspired flexible wing for FWR-MAVs, emphasizing its novel backward-curved wingtip and variable spanwise stiffness resembling a dragonfly's wing. The research departs from previous aerodynamic studies of FWR, which focused predominantly on rectangular and rigid wings, and delves into wing flexibility. Employing Computational Fluid Dynamics (CFD), Computational Structural Dynamics (CSD), and experimental measurements, the study demonstrates the aerodynamic benefits of the dragonfly-inspired FWR wingtip shape and its reinforced structure. Fluid-Structure Interaction (FSI) analysis is used to examine the effects of elastic deformation encompassing twist and bending on aerodynamic forces. The results underscore the importance of bending deformation in enhancing lift and power efficiency and propose a method for analysing variable stiffness along the wingspan using a vortex delay mechanism that is induced by delayed flapping motion. By comparing modelled and measured stiffness, the study validates the flexibility of the FWR wing, revealing optimal aerodynamic efficiency is achieved through moderate flexibility and spanwise stiffness variation. The curving leading-edge beam forming the sweep-back wingtip offers a practical approach to obtaining variable stiffness and aerodynamic benefits for FWR-MAVs. Using the same pair of dragonfly-like flexible wings, FWR-MAVs have effectively exhibited VTOL and hovering flight capabilities, spanning from a 25-g single-motor drive model to a 51-g dual-motor drive model. This research provides valuable insights into flexible wing design for FWR-MAVs, leveraging biomimicry to improve flight efficiency.

中文翻译：

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蜻蜓柔性翼可飞扑翼旋翼气动性能

从昆虫扑翼的灵感中汲取灵感，扑翼转子 (FWR) 专为微型飞行器 (MAV) 应用而开发。 FWR 具有独特的主动扑动和被动旋转运动学，可实现高升力系数和飞行效率。这项研究彻底研究了 FWR-MAV 仿生柔性机翼的空气动力学性能和设计，强调其新颖的后弯曲翼尖和类似于蜻蜓翅膀的可变展向刚度。这项研究与之前主要关注矩形和刚性机翼的 FWR 空气动力学研究不同，并深入研究了机翼的灵活性。该研究采用计算流体动力学 (CFD)、计算结构动力学 (CSD) 和实验测量，展示了受蜻蜓启发的 FWR 翼尖形状及其加固结构的空气动力学优势。流固耦合 (FSI) 分析用于检查弹性变形（包括扭转和弯曲）对空气动力的影响。结果强调了弯曲变形在提高升力和功率效率方面的重要性，并提出了一种使用由延迟扑动运动引起的涡流延迟机制来分析沿翼展的可变刚度的方法。通过比较建模和测量的刚度，该研究验证了 FWR 机翼的灵活性，揭示了通过适度的灵活性和展向刚度变化可以实现最佳的空气动力效率。形成后掠翼尖的弯曲前缘梁为 FWR-MAV 提供了一种获得可变刚度和空气动力学优势的实用方法。使用同一对蜻蜓式柔性机翼，FWR-MAV有效地展示了垂直起降和悬停飞行能力，从25克单电机驱动型号到51克双电机驱动型号。这项研究为 FWR-MAV 的灵活机翼设计提供了宝贵的见解，利用仿生学提高飞行效率。