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

1511177（柯林斯）在美国，每年有100万下肢截肢者中约有一半人会摔倒，通常是在走路时摔倒。这些福尔斯摔倒通常会导致严重的伤害，每年的医疗费用超过10亿美元。在行走过程中，特别是在不平坦的地形上，左右运动是最不稳定的，并且需要更多的主动控制来保持平衡。令人惊讶的是，很少有人知道平衡是如何影响假体的属性，影响侧到侧的运动。虽然机器人假肢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。该项目探讨了使用机器人假体控制侧到侧平衡的新方法，表征了假体参数对稳定性的影响，并建立了平衡相关性能的定量成本效益关系。它将产生新的基本了解踝关节控制在人体平衡中的作用，以及不稳定对步态和移动性其他方面的影响。该项目将开发技术，降低跌倒率，提高满意度，增强截肢者的活动能力，改善生活质量。目前正在开发增强平衡的主动、半主动和被动假肢元件，并在沿着关键尺寸方面量化其相对成本和效益，以促进合理的设计选择。这将提高医疗保健服务的效率，设备成本的增加将被治疗跌倒相关伤害的成本降低所抵消。该项目发生在一个跨学科的教育环境中，其中博士，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，以改善人民的福祉，吸引了新的参与者，科学和工程，提高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将实施成本与平衡相关收益进行了比较。实验利用先前开发的，栓系踝足假体与高保真扭矩控制在跖屈和内翻外翻方向。该工具能够快速，良好控制的测试假肢功能和控制对人类表现的影响的新类别。项目团队包括经验丰富的医生、假肢专家、企业家和研究人员，以确保医疗、临床、商业和科学相关性。 目标1：开发新的假肢控制方法，以稳定截肢者的步态。在单侧经胫骨截肢者的实验中，正在检查几种有前途的技术，包括：i）基于内外侧质心速度的每步一次踝关节蹬离功调制，研究人员先前在模拟和非残疾受试者的实验中建立了这种技术; ii）每步一次内翻-外翻扭矩调制，预计将进一步增强侧对侧的平衡; iii）每步一次的表面匹配，预期减轻地面不规则性的影响;以及iv）优化的倒置-外翻刚度，预期以低实施成本适度地改善平衡。这些方法在单独的测试中进行独立检查，然后进行比较。参与者要面对不规则的地形，这是截肢者常见的平衡挑战。表现是衡量步态变异性，代谢率，肌肉活动，自我报告的信心和偏好。目标2：稳定技术的成本效益分析。主动控制技术，如推离功调制，需要昂贵的大功率电机和大容量电池。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。实施成本的估计与实验测量的好处相结合，以确定成本和效益之间的关系，为每一个结果，并确定帕累托最优的假体特性。

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.