Dynamic flight stability in the desert locust Schistocerca gregaria
Dynamic flight stability in the desert locust Schistocerca gregaria
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DOI：
10.1242/jeb.00501
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发表时间：
2003-08-01
影响因子：
2.8
通讯作者：
Thomas, ALR
中科院分区：
文献类型：
--
作者：
Taylor, GK;Thomas, ALR
在这里，我们提供了第一个正式的定量分析动态稳定性的飞行动物。通过测量沙漠蝗虫Schistocerca gregaria的纵向静稳定性导数和质量分布，我们发现，它们的静稳定性和静态控制响应不足以提供渐近纵向动态稳定性，除非它们对俯仰姿态（相对于惯性或地球固定框架测量）以及气动入射（相对于飞行方向测量）敏感。我们没有发现证据的“恒定升力反应”，以前应该保持升力生产恒定的身体角度的范围内，并表明，这样的反应将是无关紧要的，因为蝗虫可以潜在地纠正在一个单一的翼拍间距干扰。静态稳定性导数确定了三种自然纵向运动模式：一种稳定下沉模式，一种不稳定发散模式和一种稳定振荡模式（存在或不存在俯仰姿态控制）。后者被确定为2803短周期模式的飞机，并示出由快速俯仰振荡与前进速度的变化可以忽略不计。短周期模式的频率（约10 Hz）仅为翼拍频率的一半（约10 Hz）。22 Hz），因此该模式将与没有足够阻尼的扑动周期耦合。俯仰率阻尼被证明是非常有效的，特别是在小尺度与昆虫飞行，并可能是必不可少的稳定蝗虫飞行。虽然具有接近翼拍频率的短周期模式频率有耦合的风险，但是在单个翼拍的水平上进行的控制输入是有效的是必要的。这被认为是飞行动物飞行控制的一般限制。
Here we provide the first formal quantitative analysis of dynamic stability in a flying animal. By measuring the longitudinal static stability derivatives and mass distribution of desert locusts Schistocerca gregaria, we find that their static stability and static control responses are insufficient to provide asymptotic longitudinal dynamic stability unless they are sensitive to pitch attitude (measured with respect to an inertial or earth-fixed frame) as well as aerodynamic incidence (measured relative to the direction of flight). We find no evidence for a 'constant-lift reaction', previously supposed to keep lift production constant over a range of body angles, and show that such a reaction would be inconsequential because locusts can potentially correct for pitch disturbances within a single wingbeat. The static stability derivatives identify three natural longitudinal modes of motion: one stable subsidence mode, one unstable divergence mode, and one stable oscillatory mode (which is present with or without pitch attitude control). The latter is identified with the 2803 short period mode of aircraft, and shown to consist of rapid pitch oscillations with negligible changes in forward speed. The frequency of the short period mode (approx. 10 Hz) is only half the wingbeat frequency (approx. 22 Hz), so the mode would become coupled with the flapping cycle without adequate damping. Pitch rate damping is shown to be highly effective for this purpose especially at the small scales associated with insect flight and may be essential in stabilising locust flight. Although having a short period mode frequency close to the wingbeat frequency risks coupling, it is essential for control inputs made at the level of a single wingbeat to be effective. This is identified as a general constraint on flight control in flying animals.