Collaborative Research: Integrating Optimal Function and Compliant Mechanisms for Ubiquitous Lower-Limb Powered Prostheses

合作研究：将优化功能和合规机制整合到无处不在的下肢动力假肢中

• 批准号: 2344766
• 负责人: Larry Howell
• 金额: $ 28.21万
• 依托单位: Brigham Young University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-09-01 至 2027-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2344766&HistoricalAwards=false
• 关键词: Collaborative; Research; Integrating; Optimal; Function

The majority of lower-limb prostheses are passive. They can dissipate and store mechanical power but cannot generate positive net power. The lack of power generation limits movements that require the user to move against gravity, such as going upstairs or transitioning from sitting to standing. This lack of power may induce uneven loads in the body, which can increase the likelihood of chronic back pain and increase the effort to walk. Active prostheses have the potential to overcome these fundamental challenges. However, commercially available powered prostheses are heavier, noisier, more expensive, and generally less accessible than unpowered versions. The overall goal of this project is to reimagine existing rigid prosthetic components as compliant mechanisms that reduce mass, energy consumption, audible noise, and part count of powered prostheses. Muscles take advantage of the elasticity of tendons (in series with the muscle) and ligaments (in parallel with the muscle) to efficiently transfer power from the muscle to the joints. This project will provide a new understanding of how to engineer elastic components in parallel with electric motors as engineered ligaments to make powered prostheses more attractive and accessible.The performance and behavior of compliant mechanisms depend on three fundamental factors: 1) material properties, 2) geometry, and 3) load-deflection response. This project will develop new knowledge to design the load-deflection response and geometry of compliant mechanisms that connect in parallel with electric motors to reduce motor torque. This reduction implies lighter, more energy-efficient, and quieter prostheses, as it requires lower reduction ratios, fewer gears meshing, lighter motors, and less heat dissipation. This collaborative project between the University of Notre Dame and Brigham Young University will establish two scientific contributions: 1) a robust convex optimization framework to design the load-deflection response of a parallel spring that guarantees motor torque reduction in multiple locomotion activities despite parametric uncertainty (e.g., user mass, walking speed); and 2) a design framework for compliant mechanisms with optimal load-deflection profiles to reimagine existing rigid components and implement the benefits of parallel compliance without a tradeoff in terms of mechanical complexity or extra components. The application of these innovations will result in an Open-Source Compliant Ankle, with open-source designs available online that complement the existing NSF-funded Open-Source Leg. The research team will collaborate with non-profit organization 2ft Prosthetics and local Amputee Support Groups to incorporate the feedback from prosthetic users, manufacturers, and clinicians into new designs. The outcomes of this research will include the organization of a conference workshop, new content in a graduate-level class on Wearable Robotics, and a 3-week summer program for local middle schoolers interested in STEM education.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.

大多数下肢假肢都是被动的。它们可以耗散和存储机械功率，但不能产生正净功率。缺乏发电限制了需要用户克服重力移动的运动，例如上楼或从坐到站的转变。 这种动力不足可能会导致身体负荷不均匀，从而增加慢性背痛的可能性并增加行走的难度。主动假肢有潜力克服这些基本挑战。然而，市售的动力假肢比无动力假肢更重、噪音更大、更昂贵，并且通常更难使用。该项目的总体目标是将现有的刚性假肢部件重新构想为顺应机制，以减少动力假肢的质量、能耗、可闻噪音和零件数量。肌肉利用肌腱（与肌肉串联）和韧带（与肌肉平行）的弹性，有效地将力量从肌肉传递到关节。该项目将为如何将弹性组件与电动机并行设计为工程韧带提供新的理解，以使动力假肢更具吸引力和更容易使用。顺应机构的性能和行为取决于三个基本因素：1）材料特性，2）几何形状，3) 载荷-挠度响应。该项目将开发新知识来设计与电动机并联连接以减少电动机扭矩的顺从机构的负载偏转响应和几何形状。这种减少意味着假肢更轻、更节能、更安静，因为它需要更低的减速比、更少的齿轮啮合、更轻的电机和更少的散热。圣母大学和杨百翰大学之间的这个合作项目将做出两项科学贡献：1）一个强大的凸优化框架，用于设计平行弹簧的负载偏转响应，尽管存在参数不确定性，但仍能保证多种运动活动中电机扭矩的减小（例如，用户质量、步行速度）； 2) 具有最佳负载偏转曲线的柔顺机构设计框架，可重新构想现有刚性组件并实现并行柔顺的优势，而无需在机械复杂性或额外组件方面进行权衡。这些创新的应用将产生符合开源标准的脚踝，并可在线获取开源设计，以补充现有的 NSF 资助的开源腿。研究团队将与非营利组织 2ft Prosthetics 和当地截肢者支持小组合作，将假肢用户、制造商和临床医生的反馈纳入新设计中。这项研究的成果将包括组织会议研讨会、可穿戴机器人研究生课程的新内容，以及为对 STEM 教育感兴趣的当地中学生举办为期 3 周的暑期项目。该奖项反映了 NSF 的法定使命，并已通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。