Wiggin M Bruce, Sawicki Gregory S, Collins Steven H
Joint Department of Biomedical Engineering, North Carolina State University and UNC-Chapel Hill, Raleigh, NC, USA.
IEEE Int Conf Rehabil Robot. 2011;2011:5975342. doi: 10.1109/ICORR.2011.5975342.
Symmetric ankle propulsion is the cornerstone of efficient human walking. The ankle plantar flexors provide the majority of the mechanical work for the step-to-step transition and much of this work is delivered via elastic recoil from the Achilles' tendon - making it highly efficient. Even though the plantar flexors play a central role in propulsion, body-weight support and swing initiation during walking, very few assistive devices have focused on aiding ankle plantarflexion. Our goal was to develop a portable ankle exoskeleton taking inspiration from the passive elastic mechanisms at play in the human triceps surae-Achilles' tendon complex during walking. The challenge was to use parallel springs to provide ankle joint mechanical assistance during stance phase but allow free ankle rotation during swing phase. To do this we developed a novel smart-clutch' that can engage and disengage a parallel spring based only on ankle kinematic state. The system is purely passive - containing no motors, electronics or external power supply. This energy-neutral' ankle exoskeleton could be used to restore symmetry and reduce metabolic energy expenditure of walking in populations with weak ankle plantar flexors (e.g. stroke, spinal cord injury, normal aging).
对称的踝关节推进是高效人类行走的基石。踝关节跖屈肌为步幅转换提供了大部分机械功，其中很大一部分功是通过跟腱的弹性回弹来实现的，这使得行走效率极高。尽管跖屈肌在行走过程中的推进、体重支撑和摆动启动中起着核心作用，但很少有辅助装置专注于辅助踝关节跖屈。我们的目标是开发一种便携式踝关节外骨骼，其灵感来源于人类小腿三头肌 - 跟腱复合体在行走过程中发挥作用的被动弹性机制。面临的挑战是使用平行弹簧在站立阶段为踝关节提供机械辅助，但在摆动阶段允许踝关节自由旋转。为此，我们开发了一种新型的“智能离合器”，它可以仅根据踝关节的运动状态来接合和分离平行弹簧。该系统完全是被动的，不包含电机、电子设备或外部电源。这种“能量中性”的踝关节外骨骼可用于恢复踝关节跖屈无力人群（如中风、脊髓损伤、正常衰老人群）行走的对称性并减少代谢能量消耗。
