CDS&E: Computational and Experimental Studies on Dynamic Interactions With Soft Soil

软土上的运动对于许多导航和勘探作业都很重要，包括沿海、石油和淡水资源勘探、地外地形导航、矿山和辐射探测测绘作业以及搜索和救援作业。一般来说，在柔软或松散的土壤上的运动比在包装表面上的运动需要高的能量消耗。通过该奖项的支持，将继续进行基础研究，以进一步了解机车与不同颗粒介质的相互作用。这项研究将借鉴不同领域的知识，包括土壤模型、数值模拟、车辆动力学和数据挖掘。一个显著的影响预计将是我们对颗粒介质中车辆机动性的理解和能源效率相关策略的进步。跨学科的研究将为研究人员提供特殊的学习机会，也将迎来在计算建模和科学方面受过训练的新一代研究人员。在团队先前在计算和实验动力学、非线性现象和流固相互作用方面的努力的指导下，这项研究工作将侧重于理解软土壤上与轮式和腿式运动相关的颗粒介质相互作用。原始实验将使用光弹性颗粒来检查颗粒间力链的发展，以响应外部负载产生的局部表面扰动。这些实验有望为基于离散元素模型的颗粒相互作用模拟生成数据。这些模拟将利用GPU计算。连续体，地质力学-流体动力学模拟将用于将观察到的力链与特定的土壤类型联系起来。这项研究工作将有助于回答以下基本问题：1)力链能否用于预测软土相互作用中的滑动？ii)是否存在使土壤打滑最小化的最佳步速？iii)结合复杂的摩擦模型，球体能否在统计平均意义上准确模拟砂粒和其他非球形物体的相互作用？iv)是否可以将统计分布（如Tracy-Widom分布）应用于与颗粒介质的相互作用？研究结果有望提供一种独特的方法，以一种无法通过单独实验处理的方式来询问机车相互作用的颗粒反应。研究结果预计将有助于为跨越不同尺寸、重量、速度和能耗目标的机器人平台开发有效的推进策略。

Locomotion on soft soil is important for many navigation and exploration operations, including explorations for coastal, petroleum, and fresh water resources, extraterrestrial terrain navigation, mapping operations for mine and radiation detection, and search and rescue operations. In general, motions on soft or loose soil require high energy expenditures compared to motions on packed surfaces. Through support of this award, fundamental research will be pursued to gain further understanding of locomotive interactions with different granular media. This research will draw upon knowledge from various areas, including soil modeling, numerical simulations, vehicle dynamics, and data mining. A salient impact is expected to be the advancement of our understanding of vehicle maneuverability in granular media and related strategies for energy efficiency. The cross-disciplinary research will provide exceptional learning opportunities for the researchers involved and also usher in new generation of researchers trained in computational modeling and sciences. Guided by the team's prior efforts in computational and experimental dynamics, nonlinear phenomena, and fluid-structure interactions, this research effort will be pursued with a focus on understanding granular media interactions associated with wheeled and legged locomotion on soft soils. Original experiments will be conducted by using photo-elastic granules to examine inter-granular force chain development in response to local surface disturbances generated by external loading. These experiments are expected to generate data for simulations of granular interactions based on discrete element models. These simulations will leverage GPU computing. Continuum, geomechanical-hydrodynamic simulations will be used to associate observed force chains with specific soil types. The research effort will help answer basic questions such as the following: i) Can force chains be used to predict slipping in soft-soil interactions? ii) Does an optimum gait speed exist at which soil slipping is minimized? iii) Can spheres, combined with complex friction models, accurately simulate interactions of sand grains and other non-spherically shaped bodies in a statistically averaged sense? and iv) Can one apply statistical distributions such as the Tracy-Widom distribution to interactions with granular media? The findings are expected to provide a unique means for interrogating granular reactions to locomotive interactions in a way not tractable through experimentation alone. The outcomes are expected to be useful for developing efficient propulsion strategies for robot platforms that span a range of different sizes, weights, speeds, and energy consumption targets.