UNS: Development and Comparison of New Methods for Stabilizing Amputee Gait

1511177（Collins）在美国，每年大约有100万下肢截肢者中有一半经历过跌倒，通常是在走路的时候。这些跌倒常常导致严重的伤害，每年的医疗费用超过10亿美元。行走时左右运动最不稳定，特别是在不平坦的地形上，需要更多的主动控制来保持平衡。令人惊讶的是，人们对影响左右运动的假体特性如何影响平衡知之甚少。虽然机器人假肢已经改善了推进力和能源成本，但这项技术尚未用于提高稳定性或降低跌倒风险。本项目探索了利用机器人假肢控制左右平衡的新方法，表征了假肢参数对稳定性的影响，并建立了与平衡相关性能的定量成本效益关系。它将产生对踝关节控制在人体平衡中的作用以及不稳定性对步态和活动的其他方面的影响的新的基本理解。该项目将开发技术，减少跌倒率，提高满意度，增强截肢患者的行动能力，提高生活质量。增强平衡性的主动、半主动和被动假肢元件正在开发中，它们的相对成本和效益沿着关键维度进行量化，促进合理的设计选择。这将导致医疗保健服务效率的提高，治疗跌倒相关伤害的费用减少将抵消设备成本的增加。该项目在跨学科的教育环境中进行，博士，硕士和本科生与临床专家互动，并获得开发技术以解决残疾问题的经验。这种引人注目的技术应用改善了人们的福祉，吸引了新的科学和工程参与者，增加了女性和少数民族学生的招聘。一个私营部门的合作伙伴正在帮助解决商业翻译问题。该项目建立了稳定截肢者步态的新技术，并在稳定性、代谢能量使用和平衡信心方面比较了实施成本与平衡相关的益处。实验利用先前开发的系留踝足假体，在跖屈曲和倒转-外翻方向上具有高保真扭矩控制。该工具可以实现一种新型的快速、控制良好的测试，以检测假体特征和控制对人体性能的影响。项目团队包括经验丰富的医生、义肢专家、企业家和研究人员，以确保在医疗、临床、商业和科学方面的相关性。该项目的主要目标是：目标1：开发新的假肢控制方法来稳定截肢者的步态。一些有前途的技术正在对单侧胫骨截肢者进行实验，包括：i)基于内侧外侧质心速度每一步一次的踝关节推离工作调节，这是研究人员之前在非残疾受试者的模拟和实验中建立的一种技术；Ii)每步一次的反转转矩调制，有望进一步增强左右平衡；Iii)每步一次的地面匹配，有望减轻地面不规则的影响；iv)优化了倒转刚度，期望在较低的实施成本下适度改善平衡。这些方法在单独的测试中进行独立检验，然后进行比较。参与者要面对不规则的地形，这对截肢者来说是一个常见的平衡挑战。表现是根据步态变异性、代谢率、肌肉活动和自我报告的信心和偏好来衡量的。目标2：稳定技术的成本效益分析。主动控制技术，如推断工作调制，需要昂贵的高功率电机和大电池。半主动技术，如表面匹配，可以用更小、更便宜的驱动方案来实现。估算的实施成本与实验测量的收益相结合，以确定每个结果的成本和收益之间的关系，并确定帕累托最优假体特征。

1511177(Collins)About half of the one million people in the United States with lower-limb amputation experience a fall each year, usually during walking. These falls often result in serious injury, with annual health care costs of over one billion dollars. Side-to-side motions are least stable during walking, especially on uneven terrain, and require more active control for balance. Surprisingly, little is known about how balance is affected by prosthesis properties that influence side-to-side motions. While robotic prostheses have improved propulsion and energy cost, this technology has not yet been used to improve stability or reduce fall risk. This project explores new approaches to the control of side-to-side balance using robotic prostheses, characterizes the effects of prosthesis parameters on stability, and establishes quantitative cost-benefit relationships for balance-related performance. It will yield new fundamental understanding of the role of ankle control in human balance and of the impact of instability on other aspects of gait and mobility. The project will develop technologies that lead to reduced fall rates, increased satisfaction and enhanced mobility for individuals with amputation, improving quality of life. Active, semi-active and passive prosthesis elements that enhance balance are being developed and their relative costs and benefits quantified along key dimensions, facilitating rational design choices. This will lead to increased efficiency in health care delivery, with increases in device cost being offset by reductions in costs for treating fall-related injuries. This project takes place in an interdisciplinary educational setting, in which doctoral, Master's and undergraduate students interact with clinical experts and gain experience in developing technologies to address disability. This compelling application of technology to improve people's well-being attracts new participants to science and engineering, enhancing the recruitment of female and minority students. A private-sector partner is helping to address commercial translation.This project establishes new techniques for stabilizing amputee gait and compares implementation costs to balance-related benefits in terms of stability, metabolic energy use, and balance confidence. Experiments utilize a previously-developed, tethered ankle-foot prosthesis with high-fidelity torque control in both plantarflexion and inversion-eversion directions. This tool enables a new class of rapid, well-controlled tests of the effects of prosthesis features and control on human performance. The project team includes experienced physicians, prosthetists, entrepreneurs and researchers to ensure medical, clinical, commercial and scientific relevance. The primary goals of the project are: Goal 1: Develop new prosthesis control methods to stabilize amputee gait. Several promising techniques are being examined in experiments with unilateral trans-tibial amputees, including: i) once-per-step ankle push-off work modulation based on medial-lateral center of mass velocity, a technique the investigators previously established in simulations and experiments with non-disabled subjects; ii) once-per-step inversion-eversion torque modulation, expected to further enhance side-to-side balance; iii) once-per-step surface matching, expected to mitigate the effects of ground irregularities; and iv) optimized inversion-eversion stiffness, expected to modestly improve balance at low implementation cost. These methods are independently examined in separate tests and then compared. Participants are subjected to irregular terrain, a common balancing challenge for amputees. Performance is measured in terms of gait variability, metabolic rate, muscle activity, and self-reported confidence and preference. Goal 2: Cost-benefit analysis of stabilization techniques. Active control techniques, such as push-off work modulation, require expensive, high-power motors and large batteries. Semi-active techniques, such as surface matching, could be implemented with smaller, less-expensive actuation schemes. Estimates of implementation costs are combined with experimentally measured benefits to determine relationships between cost and benefit for each outcome and identify Pareto-optimal prosthesis characteristics.