PDF(Pubmed)
Abstract：
Creating burrows through natural soils and sediments is a problem that evolution has solved numerous times, yet burrowing locomotion is challenging for biomimetic robots. As for every type of locomotion, forward thrust must overcome resistance forces. In burrowing, these forces will depend on the sediment mechanical properties that can vary with grain size and packing density, water saturation, organic matter and depth. The burrower typically cannot change these environmental properties, but can employ common strategies to move through a range of sediments. Here we propose four challenges for burrowers to solve. First, the burrower has to create space in a solid substrate, overcoming resistance by e.g., excavation, fracture, compression, or fluidization. Second, the burrower needs to locomote into the confined space. A compliant body helps fit into the possibly irregular space, but reaching the new space requires non-rigid kinematics such as longitudinal extension through peristalsis, unbending, or eversion. Third, to generate the required thrust to overcome resistance, the burrower needs to anchor within the burrow. Anchoring can be achieved through anisotropic friction or radial expansion, or both. Fourth, the burrower must sense and navigate to adapt the burrow shape to avoid or access different parts of the environment. Our hope is that by breaking the complexity of burrowing into these component challenges, engineers will be better able to learn from biology, since animal performance tends to exceed that of their robotic counterparts. Since body size strongly affects space creation, scaling may be a limiting factor for burrowing robotics, which are typically built at larger scales. Small robots are becoming increasingly feasible, and larger robots with non-biologically-inspired anteriors (or that traverse pre-existing tunnels) can benefit from a deeper understanding of the breadth of biological solutions in current literature and to be explored by continued research.
摘要：
通过自然土壤和沉积物创造洞穴是进化多次解决的问题，然而，挖掘运动对仿生机器人来说是一个挑战。至于每种运动，向前推力必须克服阻力。在挖洞中，这些力将取决于沉积物的机械性能，这些机械性能可以随晶粒尺寸和堆积密度而变化，含水饱和度,有机物和深度。挖洞者通常不能改变这些环境属性，但可以采用共同的策略在一系列沉积物中移动。在这里，我们提出了挖掘者要解决的四个挑战。首先,挖洞者必须在固体基质中创造空间，克服阻力，例如，开挖,骨折,压缩，或流化。第二,挖洞者需要进入密闭空间。顺从的身体有助于适应可能不规则的空间，但是到达新空间需要非刚性运动学，例如通过蠕动纵向延伸，不屈不挠，或外翻。第三，产生所需的推力来克服阻力，挖洞者需要锚定在洞穴内。锚固可以通过各向异性摩擦或径向膨胀来实现，或者两者兼而有之。第四，挖洞者必须感知和导航以适应洞穴形状，以避免或进入环境的不同部分。我们的希望是，通过打破探究这些组成部分挑战的复杂性，工程师将能够更好地从生物学中学习，因为动物的表现往往超过机器人的表现。因为身体大小强烈影响空间的创造，缩放可能是挖掘机器人的限制因素，它们通常是以更大的规模建造的。小型机器人正变得越来越可行，和具有非生物启发的前部（或穿越预先存在的隧道）的大型机器人可以从对当前文献中生物解决方案的广度的更深入理解中受益，并将通过持续的研究进行探索。
