A flapping-wing micro air vehicle (FW-MAV) operating with aerodynamically optimal wing configuration and kinematics may save energy and thus prolong flight time. In this work, we use a computational-fluid-dynamic method to investigate the effects of wing kinematics, corrugation structures, and clap-and-fling on the aerodynamic efficiency of our hovering two-winged FW-MAV (KUBeetle). From the measured reference wing kinematics, we generated several different wing kinematics, considering the effect of spanwise twist and chordwise camber that produce high lift-to-drag ratio (L/D). Among the investigated cases, the modified wing kinematics version 3, which includes both camber and twist with an average angle of attack of about 37°, was selected, because of its ∼24% improvement of L/D, while maintaining similar lift to the measured reference wing kinematics. The results also showed that the camber plays a role in the improvement of both lift and L/D, which improvements are approximately (16.7 and 10.6)%, respectively. We then used wing kinematics version 3 to investigate the effects of various leading-edge corrugation structures. Based on the results of lift and L/D, we proposed a wing with distributed wing corrugations along the wingspan, which slightly augments the L/D by 2%. In addition, to see how the clap-and-fling behavior contributes to the aerodynamic efficiency, its effects on lift and drag generation were examined. We found that the clap-and-fling enhanced lift by 5%, but increased drag by 9%, resulting in a 4% reduction of the L/D for both the measured and the modified wing kinematics. Thus, the lift-augmented clap-and-fling is inefficient for FW-MAVs. Finally, the study confirmed that the wing with distributed wing corrugations using wing kinematics version 3 without clap-and-fling presented at the stroke reversals is preferable for the high aerodynamic efficiency of the KUBeetle robot, with 31% improvement in L/D.

以空气动力学优化机翼配置和运动学运行的扑翼微型飞行器 (FW-MAV) 可以节省能源，从而延长飞行时间。在这项工作中，我们使用计算流体动力学方法来研究机翼运动学、波纹结构和拍手对我们的悬停双翼 FW-MAV (KUBeetle) 空气动力学效率的影响。根据测量的参考机翼运动学，我们生成了几种不同的机翼运动学，考虑到产生高升阻比 ( L / D )的展向扭曲和弦向弯度的影响。在所调查的案例中，选择了修改后的机翼运动学版本 3，其中包括平均迎角约为 37° 的弯度和扭曲，因为其提高了约 24%L / D，同时保持与测量参考机翼运动学相似的升力。结果还表明，外倾角对升力和L / D 的改进都有作用，改进分别约为（16.7 和 10.6）%。然后，我们使用机翼运动学版本 3 来研究各种前缘波纹结构的影响。基于升力和L / D的结果，我们提出了一种沿翼展分布有翼波纹的机翼，这略微增加了L / D2%。此外，为了了解拍手和抛掷行为如何影响空气动力学效率，研究了其对升力和阻力产生的影响。我们发现拍击和抛掷使升力提高了 5%，但阻力增加了 9%，导致测量的和修改后的机翼运动学的L / D减少了 4% 。因此，对于 FW-MAV 来说，升力增强的拍手和投掷是低效的。最后，研究证实，使用机翼运动学版本 3 的具有分布式机翼波纹的机翼在行程反转时不会出现拍手和甩动，这对于 KUBeetle 机器人的高空气动力学效率是可取的，L / D提高了 31% 。