Mitigating memory effects during undulatory locomotion on hysteretic materials
Mitigating memory effects during undulatory locomotion on hysteretic materials
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DOI：
10.1101/748186
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发表时间：
2019-08
期刊：
影响因子：
7.7
通讯作者：
Perrin E. Schiebel;Henry C. Astley;Jennifer M. Rieser;Shashank Agarwal;Christian M. Hubicki;Alex M. Hubbard;K. Cruz;J. Mendelson;K. Kamrin;D. Goldman
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作者：
Perrin E. Schiebel;Henry C. Astley;Jennifer M. Rieser;Shashank Agarwal;Christian M. Hubicki;Alex M. Hubbard;K. Cruz;J. Mendelson;K. Kamrin;D. Goldman
人们对水等流动介质中的波动性游泳进行了充分研究，但对于因身体与基质相互作用而永久变形的环境中的运动知之甚少，例如沙子中的蛇、泥土中的鳗鱼和腐烂水果中的线虫。我们研究了穿越颗粒物质的沙漠专家蛇 Chion-actis occipitalis，发现尽管快速移动和速度依赖的颗粒反作用力，身体惯性可以忽略不计。新的表面阻力理论（RFT）计算揭示了这种蛇形波形如何最大限度地减少记忆效应并在给定生理限制（功率）的情况下优化逃生性能。 RFT 解释了各种非沙子专家的形态和波形相关性能，但高估了具有高滑移的蛇的能力。机器人物理实验概括了这些容易出现故障的蛇的各个方面，并阐明了重新遇到先前改造的材料如何影响性能。这项研究揭示了我们之前的研究中记忆效应如何阻碍多种蛇的运动[Marvi et al, Science, 2014]，并表明存在历史依赖的颗粒物理学的预测模型。
Undulatory swimming in flowing media like water is well-studied, but little is known about loco-motion in environments that are permanently deformed by body–substrate interactions like snakes in sand, eels in mud, and nematode worms in rotting fruit. We study the desert-specialist snake Chion-actis occipitalis traversing granular matter and find body inertia is negligible despite rapid transit and speed dependent granular reaction forces. New surface resistive force theory (RFT) calculation reveals how this snakes wave shape minimizes memory effects and optimizes escape performance given physiological limitations (power). RFT explains the morphology and waveform dependent performance of a diversity of non-sand-specialist, but overpredicts the capability of snakes with high slip. Robophysical experiments recapitulate aspects of these failure-prone snakes and elucidate how reencountering previously remodeled material hinders performance. This study reveals how memory effects stymied the locomotion of a diversity of snakes in our previous studies [Marvi et al, Science, 2014] and suggests the existence of a predictive model for history-dependent granular physics.