CAREER: Steerable Powered Ankle-foot Prostheses for Increased Mobility in Amputees

1350154 Rastgaar概述：行动能力是幸福的关键因素，无论是在情感上(通过增加独立性，减少抑郁和焦虑)，在身体上(通过降低疾病风险、骨骼维护、肌肉力量和体重控制)。超过一百万的美国公民是截肢者，主要是小腿截肢者。这项职业计划将1)通过研究动力踝足假体的设计和控制来提高下肢截肢者的灵活性，这种假体具有两个可控自由度(DOF)，模拟人类步态的转向机制；2)将研究与教育和推广相结合，以激励和装备多样化的下一代工程师。为了朝着这些长远目标努力，这个职业计划还会发展吗？并用于教育和推广-一种轻型、缆绳驱动的动力踝足假体，能够通过学习人类步态中矢状面和额面的踝关节阻抗来控制和穿越斜坡。智力优势：该项目基于这样一个假设，即能够在矢状面和额面施加扭矩和阻抗调制的踝足假体，类似于人类脚踝，将通过降低步态的新陈代谢成本来改善机动性和增加机动性--无论是笔直行走还是转弯。动力假体的进展表明，通过在推开时提供足够的能量，可以降低代谢成本，提高单侧经胫骨截肢者在直线行走时的首选步态速度。电动假体还可以减少不对称的步态模式，因此可能会降低继发性并发症的风险。然而，研究表明，根据活动的不同，转身的步数占步数的8%-50%，因此可能占日常步数的25%。踝关节阻抗在矢状面和额面的调制在控制侧向和推进地面反作用力中起主要作用。非截肢者依靠在冠状面的髋关节运动和在踝关节产生的力矩，而使用被动假体的截肢者使用矢状面的髋关节伸展作为步态策略[5-8]。这一假设得到了皮埃尔？S的初步结果的支持，该结果显示，在踏步转身的站立阶段，脚踝有较大的内翻，表明脚踝旋转与直步模式有显著偏离。了解踝关节在运动中的作用，并开发一个设计和控制新型踝足假体的平台，将使探索性研究和教育成为可能。研究将包括：推力1：估计步态站立期间矢状面和额面的脚踝阻抗；推力2：开发具有两个可控自由度的动力踝足假体；推力3：使用评估平台评估假体的设计和控制，并通过与梅奥诊所的合作评估膝盖以下截肢者的设计和控制；以及推力4：教育/外联：利用可控制的踝足假体进行教育、推广和研究，以影响不同的K-12、社区大学、本科生和研究生的体验。这项工作具有重要意义，因为它将有助于1)关于步态站立期间人体踝关节多变量阻抗调制的新知识，这是一个尚未完全探索的领域，以及2)开发和评估动力踝足假体的独特框架。这种可操纵的脚踝-脚假体具有创新性，因为它将使截肢者使用脚踝关节，而不仅仅是髋关节和膝盖，以更自然的步态行走。这一新型平台的开发将朝着皮？S的长期目标迈出实质性的一步，该目标是改善下肢辅助假肢和机器人的设计和可操作性。博大影响：机器人技术是一种高影响力的方式，可以吸引未来工程师的注意。该项目将开展外联活动，激发和维持STEM对大学前学生，特别是代表不足的少数族裔的兴趣。开发一种廉价的动力踝足假体将改善受伤战士和平民截肢者的健康状况，同时激励和培训未来的STEM劳动力。此外，PI还设计和开发了一种低成本的肌电控制机械手作为教育平台，将用于推广项目，向K-12、社区大学、本科生和研究生教授机电、机器人和生物力学基础知识。制定的外展计划将经过严格评估，然后向其他研究人员公开。

1350154RastgaarOverview: Mobility is a key factor to well-being, both emotionally (through increased independence and decreased depression and anxiety) and physically (through reduced disease risk, bone maintenance, muscle strength, and weight control). Over a million US citizens are limb amputees, primarily lower leg amputees. This CAREER program will 1) work to improve the mobility of lower extremity amputees through research in design and control of powered ankle-foot prostheses, which mimic the steering mechanism of human gait by having two controllable degrees of freedom (DOF) and 2) integrate research with education and outreach to inspire and equip a diverse next generation of engineers. To work toward these long-term goals, this CAREER program will develop ? and use in education and outreach - a lightweight, cable-driven, powered ankle-foot prosthesis capable of steering and traversing slopes by learning from human ankle impedance in the sagittal and frontal planes during gait.Intellectual Merit: This project is based on the hypothesis that an ankle-foot prosthesis capable of applying torques and impedance modulation in both the sagittal and frontal planes, similar to the human ankle, will improve maneuverability and increase mobility by lowering the metabolic cost of gait - both when walking straight and turning. Advances in powered prostheses have shown the ability to reduce metabolic cost and increase the preferred speed of gait for unilateral transtibial amputees during straight walking by providing sufficient power during push-off. Powered prostheses can also reduce asymmetrical gait patterns and thus may lower risk of secondary complications. However, studies show that turning steps account for 8-50% of steps, depending on activity, and thus may account for 25% of daily steps. Modulation of ankle impedance in the sagittal and frontal planes plays a major role in controlling lateral and propulsive ground reaction forces. While a non-amputee relies on hip movement in the coronal plane and the moment generated in the ankle joint, an amputee using a passive prosthesis uses the hip extension in the sagittal plane as a gait strategy [5-8]. The hypothesis is supported by the PI?s preliminary results which show a large inversion of the ankle during the stance period of step turns, indicating a significant deviation of ankle rotations from the straight-step pattern. Understanding the role of the ankle in locomotion and developing a platform for design and control of a new ankle-foot prostheses will allow exploratory research and education. Research will include: Thrust 1: Estimate ankle impedance in the sagittal and frontal planes during the stance period of gait; Thrust 2: Develop a powered ankle-foot prosthesis with two controllable DOF; Thrust 3: Evaluate the design and control of the prosthesis using an evaluation platform and with below-knee amputees through collaboration with Mayo Clinic; and Thrust 4: Education/Outreach: Utilize the steerable ankle-foot prosthesis for education, outreach, and research experiences to impact diverse K-12, community college, undergraduate, and graduate students. The work is significant in that it will contribute 1) new knowledge about multivariable impedance modulation of the human ankle during the stance period of gait, an area not yet fully explored, and 2) a unique framework for developing and evaluating powered ankle-foot prostheses. The steerable ankle-foot prosthesis is innovative because it will enable amputees to walk with a more natural gait by using the ankle joint, rather than merely the hip and knee. Development of this novel platform will be a substantial step toward the PI?s long-term goal of improving design and maneuverability in lower extremity assistive prostheses and robots.Broader Impacts: Robotics is a high-impact way to attract the attention of future engineers. This project will develop outreach activities that spark and sustain STEM interest in pre-college students, especially underrepresented minorities. Development of an inexpensive powered ankle-foot prosthesis will improve well-being of Wounded Warriors and civilian amputees, while at the same time inspiring and training the future STEM workforce. In addition, the PI has designed and developed a low-cost EMG-controlled manipulator as educational platform that will be used in outreach programs to teach fundamentals of mechatronics, robotics, and biomechanics to K-12, community college, undergraduate, and graduate students. The developed outreach programs will be rigorously evaluated and then made publicly available to other researchers.