Wing flexibility reduces the energetic requirements of insect flight
Wing flexibility reduces the energetic requirements of insect flight
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DOI：
10.1088/1748-3190/ab2dbc
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发表时间：
2019-09-01
影响因子：
3.4
通讯作者：
Jankauski, Mark
中科院分区：
文献类型：
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作者：
Reid, Heidi E.;Schwab, Ryan K.;Jankauski, Mark
扑动的昆虫翅膀在空气动力和惯性弹性力的作用下变形。这种变形被认为可以提高动力经济性并降低飞行的能源成本。然而，许多扑翼模型采用刚体简化或需要过多的计算能力，因此无法识别飞行能量的灵活性的影响。在这里，我们推导出一个降阶模型，能够估计的驱动力矩和相应的功率扑动，灵活的昆虫翅膀。通过驱动烟草天蛾Manducasexta（L.）用定制的单自由度机械挡板向前飞行。我们的模型以合理的精度预测测量的扭矩和瞬时功率。此外，柔性机翼模型预测的实验趋势，刚体模型不能，这表明顺应性不应该被忽视时，考虑在这个规模的飞行动力学。接下来，我们使用我们的模型来研究具有真实扑翼运动学的飞行能量学。我们发现，当机翼的自然频率大约是扑翼频率的三倍时，如果负功被存储为势能并随后被释放来做正功，则与刚性机翼相比，柔性可以减少近25%的能量消耗。机翼本身可以存储约30%的1200 μ J的总能量所需的翼拍。峰值势能存储发生在冲程反向之前。我们估计，对于体重为1.5-2.5 g的蛾，飞行所需的峰值瞬时功率为75-125 W kg（-1）。然而，这些峰值在自然昆虫飞行中可能较低，其中翅膀能够与顺应性胸部交换应变能。我们的研究结果强调了柔性在扑翼微型飞行器设计中的重要性，并建议调整柔性可以大大提高飞行器的效率。
Flapping insect wings deform under aerodynamic as well as inertial-elastic forces. This deformation is thought to improve power economy and reduce the energetic costs of flight. However, many flapping wing models employ rigid body simplifications or demand excessive computational power, and are consequently unable to identify the influence of flexibility on flight energetics. Here, we derive a reduced-order model capable of estimating the driving torques and corresponding power of flapping, flexible insect wings. We validate this model by actuating a tobacco hornworm hawkmoth Manduca sexta (L.) forewing with a custom single-degree-of-freedom mechanical flapper. Our model predicts measured torques and instantaneous power with reasonable accuracy. Moreover, the flexible wing model predicts experimental trends that rigid body models cannot, which suggests compliance should not be neglected when considering flight dynamics at this scale. Next, we use our model to investigate flight energetics with realistic flapping kinematics. We find that when the natural frequency of the wing is roughly three times that of the flapping frequency, flexibility can reduce energy expenditures by almost 25% compared to a rigid wing if negative work is stored as potential energy and subsequently released to do positive work. The wing itself can store about 30% of the 1200 mu J of total energy required over a wingbeat. Peak potential energy storage occurs immediately before stroke reversal. We estimate that for a moth weighing 1.5-2.5 g, the peak instantaneous power required for flight is 75-125 W kg(-1). However, these peak values are likely lower in natural insect flight, where the wing is able to exchange strain energy with the compliant thorax. Our findings highlight the importance of flexibility in flapping wing micro aerial vehicle design and suggest tuned flexibility can greatly improve vehicle efficiency.