摘要
本文研究蜻蜓、豆娘等使用四翅飛行的昆蟲，其前後翅拍翅相位不同對飛行之影響。以翅膀拍翅相位作為主要探討的對象，設計一組可以高頻順序帶動前後翅的翅膀機構，以此機構量測升阻力及拍攝流場結構，探討四翼動態在不同飛行形態上扮演的角色，期望應用於拍翼飛行器操作性的提升。 前人研究指出：後翅領先四分之一相位的拍撲模式能夠提供翅膀最多的升力。然而，觀察蜻蜓與豆娘的拍翅行為，我們發現：在前飛時，蜻蜓傾向後翅領先四分之一相位，但豆娘傾向前翅領先四分之一相位。此外，雖然豆娘與蜻蜓在外觀上相似，但蜻蜓的翅膀負重比約為豆娘的兩倍，蜻蜓的拍翅頻率也比豆娘快。本研究嘗試探討豆娘與蜻蜓不同的拍撲模式，除了升力係數外，考慮其他與飛行相關的特徵和配合生物特性的解釋。本實驗仿昆蟲拍翅，建立翅膀被動式旋轉的拍撲機構，使用高速攝影機拍攝，利用二維PIV流場可視化技術，觀察渦漩在不同翅相位排列下的消長關係。同時設計力感測計在機構拍翅根部，測量拍翅產生流場升阻力在週期內的變化。實驗結果顯示：因翅膀被動旋轉與拍翅相位的效應疊加，前後二翅在流場中排列成不同的幾何形狀。後翅領先使得後翅受前翅干擾減小，兩翅周圍有類似的流場形狀；而前翅領先導致後翅位於前翅的尾流區，未觀察到明顯的翼前緣渦漩產生。後翅領先的拍翅模式最可以充分利用拍撲的氣流產生升力；而前翅領先的拍翅模式會減低後翅拍翅產生的升力。然而，在前翅領先的拍翅模式，後翅的形狀阻力因來流方向被前翅改變而大大降低，故阻力比起後翅領先的拍翅模式來的小。我們可以從量測的升阻力去驗證上述情形：前翅領先的平均升阻力值皆較小，但一個拍撲週期內的波動變化也較小。 綜合以上結果，本研究提供翅膀拍翅相位的新觀點，可應用於拍撲飛行器的機構概念設計上。
並列摘要
Insects under the order Odonata such as dragonflies and damselflies have outstanding flight agility. One of the morphological features is that they modulate their flight motion with independent four wings. Preceding studies show that lift remains maximum when the forewing lags behind hindwing about a quarter stroke cycle, which is the phase relationship dragonflies prefer in forward flight and ascending. However, we observe that in the flying damselflies tend to operate their wings with the forewing leads. Herein, we demonstrate the effect of phase lag by two simple passive rotation robot wings. The aerodynamic vortex structures are illustrated by particle imaging velocimetry (PIV) techniques. Lift and drag force are measured and analyzed corresponding to wing-wake structure. The results reveal that the flight performance is strongly dependent on the phase shift between two wings. Leading edge vortex (LEV) and trailing edge vortex (TEV) are interfered by the change of flow in different phase relationships. At the phase of forewing-lead, the vorticity of the hindwing is decreased because of the forewing induced flow. Passive wing rotation in different phase relationship is also investigated. The force acting on the moving wing changes as the induced flow varies, causing different quantity of deformation, lift and drag. Damselflies seem to have evolved a different forward flight strategy from dragonflies, which lowers the power consumption but provides less total lift. Wing loading of damselfly is about half of damselfly’s, therefore, the minimum requirement of lift production is also lower. In addition, the variation of lift force and drag force within one cycle is lower. The results may be applied to future design of flight vehicles.