EFRI C3 SoRo: Strong Soft Robots--Multiscale Burrowing and Inverse Design

该项目直接解决了新兴的软机器人领域面临的主要挑战。软机器人是由本质上符合要求的材料制成的，这些材料柔软、灵活，在三维空间中移动优雅，不需要离散的关节。然而，这些高度柔顺的柔体可能被证明太弱，无法施加足够大的力来完成预期的任务。此外，人们普遍缺乏对如何最好地在可用于软机器人的材料、配置和设计的令人困惑的光谱中进行导航的理解。该项目探索了可3D打印的聚氨酯聚合物的性能，这种聚合物可以定制以提供不同的机械性能。该项目将创建高度变形结构的数学模型和计算工具，以解决寻找实现特定结构行为的材料参数和3D打印图案的“逆问题”。该项目将考虑两项目前不可行的任务，其规模大不相同。任务1是一种针对神经血管和心血管应用的毫米级患者专用软机器人导管，机器人可以在血管中轻轻移动，而不需要进行危险的手术，不会阻塞血液流动，也不会伤害患者。任务2是一个米级的机器人，可以智能地在地下挖掘，其力量水平比以前的软机器人要高得多。软机器人在血管领域的应用可以为心脏病和中风的治疗提供潜在的突破。大型挖掘机器人可能会对检查地下民用基础设施或铺设新的光缆、灌溉或输电线有利。该项目还旨在吸引高中生，并激励他们从事STEM职业，包括未来的机器人学家。该项目将为通用软机器人的反向设计建立和验证一个数学框架，该框架将：1)通过进一步推广具有梁单元和任意形状的纤维增强弹性体外壳，以及与著名的McKiben致动器相匹配的非凡的力和功率密度，来提供复杂的3-D运动学；2)实现任意指定的任务和性能要求，包括新颖的多尺度挖掘行为；以及3)通过利用高度各向异性弹性体、不可伸展的纤维和梁元素及其界面化学的3D打印材料，实现机器人的自动化制造的新方法。这种数学形式通过包含由任意期望任务指定的动态、任意形状序列的全身映射来概括传统的机器人运动学。聚氨酯化学和制造方面的双重创新将使软机器人能够超越现有软机器人的能力，并克服其施加有用力量、调节刚度和完成以前不可能完成的任务的能力方面的根本限制。该项目包括在两个特定试验台上的验证实验：(1)毫米级软机器人导管，可在血管网络中移动；(2)米级挖土机器人，能够推断土壤属性，以适应自然形成的、高度异质的土壤沉积条件下的形态和运动。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project directly addresses major challenges facing the emerging field of soft robotics. Soft robots are made of inherently compliant materials that are soft, flexible, and move gracefully in three dimensions without requiring discrete joints. However, these highly compliant soft bodies may prove too weak to exert sufficiently large forces to accomplish desired tasks. Additionally, there is a general lack of understanding of how to best navigate the bewildering spectrum of materials, configurations, and designs available to soft robotics. This project explores the properties of 3D-printable polyurethane polymers that can be customized to provide different mechanical properties. This project will create mathematical models of highly deformable structures, and computational tools to solve the "inverse problem" of finding the material parameters and 3D printing pattern that achieve a specified structural behavior. The project will consider two currently infeasible tasks at greatly different length scales. Task 1 is a millimeter-scale patient-specific soft robot catheter for neurovascular and cardiovascular applications, where the robots can gently move through blood vessels without requiring risky surgery, blocking blood flow, or injuring the patient. Task 2 is a meter-scale robot that intelligently burrows underground, with force levels much higher than previously attained by soft robots. Soft robots in the vascular application can inform potential breakthroughs for the treatment of heart disease and stroke. Large burrowing robots could prove beneficial for inspecting underground civil infrastructure or laying new fiber optic cable, irrigation, or power lines. This project is also designed to engage high school students, and inspire them to pursue STEM careers, including future roboticists.This project will establish and validate a mathematical framework for the inverse design of universal soft robots that: 1) provide sophisticated 3-D kinematics by further generalizing fiber-reinforced elastomeric enclosures with beam elements and arbitrary shapes along with exceptional force and power densities that match well-known McKibben actuators; 2) achieve arbitrarily-specified tasks and performance requirements including novel multiscale burrowing behavior; and 3) dictate a new means of robotic, automated manufacturing via 3D printed materials exploiting highly anisotropic elastomers, inextensible fibers, and beam elements and their interfacial chemistries. This mathematical formalism generalizes traditional robot kinematics via a full body mapping incorporating dynamic, arbitrary shape sequences specified by an arbitrary desired task. The coupled innovation in polyurethane chemistry and manufacturing will enable soft robots that exceed the capabilities of existing soft robots and overcome fundamental limitations in their capacity to exert useful force, modulate stiffness, and achieve previously-impossible tasks. This project includes validation experiments on two specific testbeds: (1) millimeter-scale soft robot catheters that locomote through vascular networks, and (2) meter-scale burrowing robots in soils, capable of inferring soil properties to adapt their morphology and motion to suit conditions in naturally occurring, highly heterogeneous, soil deposits.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.