Neuromechanics of Soft-bodied Locomotion

动物非常擅长在复杂多变的环境中移动，这远远超过了最先进的机器人的能力。这种适应性是可能的，因为神经系统和身体作为一个单一的“神经机械系统”与环境相互作用。在动物中，这一过程主要是由肌肉和皮肤等软组织主导的，但人们对柔软材料的运动是如何控制的却知之甚少。这个项目将通过研究神经、机械和传感机制如何促进适应性运动来回答这个问题。实验将在毛毛虫身上进行，因为它们提供了一个独特的机会，可以在自由行为时使用电生理学（记录神经元和肌肉的电活动）、动作捕捉和机械测量。除了解决我们对陆地软体动物运动的理解中大部分缺失的问题外，这些研究在机器人技术中有广泛的应用，包括攀爬机器的设计和控制，建造辅助装置和操纵器以及控制更好的假肢。了解对毛虫运动很重要的机械和感官特征也可以影响无农药害虫控制策略的发展（例如，植物表面工程），管理敏感的生态位和模拟昆虫/寄主植物相互作用。三个领域的研究将决定毛毛虫如何在不同的环境中调整它们的运动。第一种方法使用动作捕捉来分析不同基底上的步进模式（步态）和方向的变化。基质的机械特性（包括刚度、密度、曲率、回弹性、伪弹性、摩擦）将被系统地改变，以确定环境的哪些机械特征是毛毛虫的基本线索。第二种将使用植入的柔性电极阵列来监测每一种步态背后的神经元活动。环境骨架假说预测，控制体壁肌肉的运动模式会随着方向而改变，但控制握力的运动模式会决定步态。最近开发的Softworm机器人（完全柔软的3d打印爬行机器人）将用于进一步研究步态切换的机制和微动行为的进化。第三，为了开始确定软体动物是如何检测到与环境的相互作用的，将对体壁中特定的触觉神经元和其他机械感应神经元进行记录，以确定它们编码的运动以及这些运动与爬行和步态变化的关系。

Animals are remarkably good at moving in complex and changing environments, far exceeding the capability of the most advanced robots. This adaptability is possible because the nervous system and the body interact with the environment as a single "neuromechanical system". In animals, this process is dominated by soft tissues such as muscles and skin but it is largely unknown how the movements of soft materials are controlled. This project will answer this question by studying how neural, mechanical and sensing mechanisms contribute to adaptable locomotion. The experiments will be carried out on caterpillars because they provide a unique opportunity to use electrophysiology (recording the electrical activity of neurons and muscles), motion capture and mechanical measurements during free behavior. In addition to addressing issues that are largely missing from our understanding of terrestrial soft animal locomotion, these studies have wide applications in robotics including the design and control of climbing machines, building assistive devices and manipulators and for controlling better prosthetics. Understanding the mechanical and sensory features that are important for caterpillar locomotion could also impact the development of pesticide-free pest-control strategies (e.g., plant surface engineering), managing sensitive ecological niches and modeling insect/host plant interactions.Three areas of research will determine how caterpillars adjust their locomotion in different environments. The first uses motion capture to analyze the stepping patterns (gaits) on different substrates and changes in orientation. The mechanical properties of the substrate (including stiffness, density, curvature, resilience, pseudo-elasticity, friction) will be altered systematically to establish what mechanical features of the environment are essential cues for caterpillars. The second will use implanted flexible electrode arrays to monitor the activity of neurons that underlie each gait. The Environmental Skeleton hypothesis predicts that motor patterns controlling the body wall muscles will change with orientation but that motor patterns controlling grip will determine the gait. Recently developed Softworm robots (entirely soft, 3D-printed crawling robots) will be used to further examine the mechanisms of gait switching and the evolution of inching behavior. Third, to begin identifying how interactions with the environment are detected by soft animals, recordings will be made from specific groups of touch and other mechanosensing neurons in the body wall to ascertain what movements they encode and how that relates to crawling and changes in gait.