Department of Mechanical Engineering, Pennsylvania State University, University Park, PA 16802, USA.
Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA.
Proc Biol Sci. 2024 Nov;291(2035):20241268. doi: 10.1098/rspb.2024.1268. Epub 2024 Nov 20.
Hummingbirds routinely execute a variety of stunning aerobatic feats, which continue to challenge current notions of aerial agility and controlled stability in biological systems. Indeed, the control of these amazing manoeuvres is not well understood. Here, we examined how hummingbirds control a sequence of manoeuvres within milliseconds, and tested whether and when they use vision during this rapid process. We repeatedly elicited escape flights in calliope hummingbirds, removed visible light during each manoeuvre at various instants and quantified their flight kinematics and responses. We show that the escape manoeuvres were composed of rapidly controlled sequential modules including evasion, reorientation, nose-down dive, forward flight and nose-up to hover. The hummingbirds did not respond to the light removal during evasion and reorientation until a critical light-removal time; afterwards, they showed two categories of luminance-based responses that rapidly altered manoeuvring modules to terminate the escape. We also show that hummingbird manoeuvres were rate-commanded and required no active braking (i.e. their body angular velocities were proportional to the change of wing motion patterns, a trait that probably alleviates the computational demand on flight control). This work uncovers key traits of hummingbird agility, which can also inform and inspire designs for next-generation agile aerial systems.
蜂鸟经常执行各种惊人的杂技动作，这继续挑战生物系统中空中敏捷性和控制稳定性的现有概念。事实上，这些惊人动作的控制还没有被很好地理解。在这里，我们研究了蜂鸟如何在毫秒内控制一系列动作，并测试了它们在这个快速过程中是否以及何时使用视觉。我们反复在吸蜜鸟中诱发逃避飞行，在每个动作的各个瞬间去除可见光，并量化它们的飞行运动学和反应。我们表明，逃避动作是由快速控制的顺序模块组成的，包括躲避、重新定向、机头向下俯冲、向前飞行和机头向上悬停。在逃避和重新定向期间，蜂鸟不会对光的去除做出反应，直到一个关键的光去除时间；之后，它们表现出两种基于亮度的反应，这些反应迅速改变操纵模块以终止逃避。我们还表明，蜂鸟的动作是速度指令的，不需要主动刹车（即它们的身体角速度与翅膀运动模式的变化成正比，这一特征可能减轻了飞行控制的计算需求）。这项工作揭示了蜂鸟敏捷性的关键特征，这也可以为下一代敏捷空中系统的设计提供信息和灵感。
