Piñeirua Miguel, Verbe Anna, Casas Jérôme
Institut de Recherche sur la Biologie de l'Insecte, Université François Rabelais, 37000 Tours, France.
Phys Rev E. 2023 Jul;108(1-1):014903. doi: 10.1103/PhysRevE.108.014903.
Locomotion on granular inclines is a subject of high relevance in ecological physics as well as in biomimmetics and robotics. Enhancing stability on granular materials represents a huge challenge due to the fluidization transition when inclination approaches the avalanche angle. Our motivating example is the predator-prey system made of the antlion, its pit, and its prey. Recent studies have demonstrated that stability on granular inclines strongly depends on the pressure exerted on the substrate. In this work we show that for multilegged locomotion, along with pressure, the distance between the leg contacts on the substrate also plays a major role in the determination of the stability threshold. Through a set of model experiments using artificial sliders, we determine a critical distance below which stability is importantly affected by the interactions between the perturbed regions generated by each contact point. A simple model based on the Coulomb method of wedges allows us to estimate a stability criterion based on pressure, interleg distance, and substrate characteristics. Our work suggests that mass to leg-length allometric relationships, as the ones observed in ants, may be an important key in determining the locomotion success of multilegged locomotion on granular inclines.
在颗粒状斜坡上的运动是生态物理学、仿生学和机器人技术中高度相关的主题。由于当倾斜度接近雪崩角时会发生流化转变，因此提高在颗粒材料上的稳定性是一项巨大的挑战。我们的动机示例是由蚁狮、其陷阱及其猎物组成的捕食者 - 猎物系统。最近的研究表明，在颗粒状斜坡上的稳定性很大程度上取决于施加在基质上的压力。在这项工作中，我们表明，对于多足运动，除了压力之外，腿部在基质上的接触点之间的距离在确定稳定性阈值方面也起着重要作用。通过一组使用人工滑块的模型实验，我们确定了一个临界距离，低于该距离时，每个接触点产生的扰动区域之间的相互作用会对稳定性产生重要影响。基于库仑楔体法的简单模型使我们能够基于压力、腿间距和基质特性估计稳定性标准。我们的工作表明，正如在蚂蚁中观察到的那样，质量与腿长的异速生长关系可能是决定多足动物在颗粒状斜坡上运动成功的重要关键。
