Robotic leg prostheses promise to improve the mobility and quality of life of millions of individuals with lower-limb amputations by imitating the biomechanics of the missing biological leg. Unfortunately, existing powered prostheses are much heavier and bigger and have shorter battery life than conventional passive prostheses, severely limiting their clinical viability and utility in the daily life of amputees. Here, we present a robotic leg prosthesis that replicates the key biomechanical functions of the biological knee, ankle, and toe in the sagittal plane while matching the weight, size, and battery life of conventional microprocessor-controlled prostheses. The powered knee joint uses a unique torque-sensitive mechanism combining the benefits of elastic actuators with that of variable transmissions. A single actuator powers the ankle and toe joints through a compliant, underactuated mechanism. Because the biological toe dissipates energy while the biological ankle injects energy into the gait cycle, this underactuated system regenerates substantial mechanical energy and replicates the key biomechanical functions of the ankle/foot complex during walking. A compact prosthesis frame encloses all mechanical and electrical components for increased robustness and efficiency. Preclinical tests with three individuals with above-knee amputation show that the proposed robotic leg prosthesis allows for common ambulation activities with close to normative kinematics and kinetics. Using an optional passive mode, users can walk on level ground indefinitely without charging the battery, which has not been shown with any other powered or microprocessor-controlled prostheses. A prosthesis with these characteristics has the potential to improve real-world mobility in individuals with above-knee amputation.

中文翻译：

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复制膝关节、踝关节和脚趾关节生物力学的轻型机械腿假肢


机器人假肢有望通过模仿缺失生物腿的生物力学，改善数百万下肢截肢者的活动能力和生活质量。不幸的是，现有的动力假肢比传统的被动假肢更重、更大，电池寿命更短，严重限制了它们的临床可行性和截肢者日常生活中的实用性。在这里，我们提出了一种机器人腿假肢，它在矢状面上复制了生物膝盖、脚踝和脚趾的关键生物力学功能，同时与传统微处理器控制假肢的重量、尺寸和电池寿命相匹配。动力膝关节采用独特的扭矩敏感机构，结合了弹性执行器和可变传动装置的优点。单个执行器通过柔顺的欠驱动机构为踝关节和脚趾关节提供动力。由于生物脚趾消耗能量，而生物脚踝将能量注入步态周期，因此该欠驱动系统可再生大量机械能，并在行走过程中复制脚踝/脚复合体的关键生物力学功能。紧凑的假肢框架封装了所有机械和电气部件，以提高坚固性和效率。对三名膝上截肢患者进行的临床前测试表明，所提出的机器人腿假肢允许进行常见的行走活动，且具有接近规范的运动学和动力学。使用可选的被动模式，用户可以无限期地在水平地面上行走，而无需给电池充电，这是任何其他动力或微处理器控制的假肢都没有表现出来的。 具有这些特性的假肢有可能改善膝上截肢患者在现实世界中的活动能力。