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

总体而言：流动性是健康的关键因素，无论是在情感上（通过增加独立性和减少抑郁和焦虑）还是在身体上（通过减少疾病风险、骨骼维护、肌肉力量和体重控制）。超过一百万的美国公民是肢体截肢者，主要是下肢截肢者。这个职业项目将1)通过研究动力踝足假肢的设计和控制来改善下肢截肢者的行动能力，该假肢通过两个可控自由度（DOF）模仿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。为了实现这些长期目标，这个职业计划将会发展？并用于教育和推广——一种轻便的、电缆驱动的、动力踝足假肢，能够通过学习人类脚踝在步态中矢状面和正面面的阻抗来转向和穿越斜坡。智力优势：这个项目是基于这样的假设：一种踝足假体能够在矢状面和额状面施加扭矩和阻抗调制，类似于人类的脚踝，将通过降低步态的代谢成本来提高机动性和增加机动性——无论是直走还是转弯。动力假肢的进步已经表明，通过在推动过程中提供足够的动力，能够降低代谢成本，并增加单侧经胫截肢者在直线行走时的首选步态速度。动力假肢还可以减少不对称的步态模式，从而降低继发性并发症的风险。然而，研究表明，根据活动的不同，转身步数占步数的8-50%，因此可能占每日步数的25%。踝关节矢状面和前面阻抗的调节在控制侧向和推进地面反作用力方面起着重要作用。非截肢者依赖于髋关节在冠状面运动和踝关节产生的力矩，而使用被动假肢的截肢者则将髋关节在矢状面伸展作为一种步态策略[5-8]。假设得到PI的支持？S的初步结果显示，在步转的站位期间，踝关节有很大的内翻，表明踝关节旋转与直步模式有明显的偏差。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关节-足假体的平台，将有助于探索性研究和教育。研究将包括：推力1：估计步态站立期间踝关节矢状面和额平面的阻抗；研究方向2：开发具有两自由度可控的动力踝足假体；推力3：通过与梅奥诊所合作，使用评估平台评估假体的设计和控制，并与膝盖以下截肢者一起评估；和推力4：教育/推广：利用可操纵的踝足假体进行教育，推广和研究经验，以影响不同的K-12，社区学院，本科生和研究生。这项工作具有重要意义，因为它将贡献1)关于人类脚踝在步态站立期间的多变量阻抗调制的新知识，这是一个尚未充分探索的领域，以及2)开发和评估动力踝足假体的独特框架。这种可操纵的踝足假体是一种创新，因为它将使截肢者通过使用踝关节，而不仅仅是臀部和膝盖，以更自然的步态行走。这个新平台的开发将是迈向PI的重要一步。我们的长期目标是改善下肢辅助假肢和机器人的设计和可操作性。更广泛的影响：机器人技术是一种吸引未来工程师注意力的高影响力方式。该项目将开展外展活动，激发和维持大学预科学生，特别是代表性不足的少数民族对STEM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福祉，同时激励和培训未来的STEM劳动力。此外，PI还设计并开发了一种低成本的肌电控制机械臂，作为教育平台，将用于向K-12、社区学院、本科生和研究生教授机电、机器人和生物力学基础知识的推广计划。开发的外展计划将被严格评估，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.