A Highly Backdrivable, Lightweight Knee Actuator for Investigating Gait in Stroke.
A Highly Backdrivable, Lightweight Knee Actuator for Investigating Gait in Stroke.
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DOI：
10.1109/tro.2009.2019788
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发表时间：
2009-06
期刊：
影响因子：
--
通讯作者：
Patton JL
中科院分区：
文献类型：
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作者：
Sulzer JS;Roiz RA;Peshkin MA;Patton JL
许多在中风中幸存下来的人患上了一种被称为膝关节僵硬步态(SKG)的步态残疾。以摆动时膝关节屈曲角度减小为特征的SKG患者，由于需要补偿机制来清理脚部，步行能量效率较低且不对称。以前的建模研究表明，在脚离开地面之前，膝关节直接进行屈膝活动，这应该会在挥杆过程中改善膝关节屈曲角度。这项研究的目标是使用机器人干预来对这一假设进行物理检验。我们开发了一种设备，能够在挥杆前帮助膝盖屈曲扭矩，但在步态周期的其余部分感觉不到(透明)。该设备使用护套鲍登电缆来控制柔顺扭转弹簧的挠度，该配置称为系列弹性远程膝部致动器(SERKA)。在这项研究中，我们描述了SERKA的设计和评估，其中包括一项针对中风受试者的初步实验。SERKA能在不到20ms的时间内提供相当大的扭矩(12N·m)，最大扭矩为41N·m。在正常步态下，该装置可以在需要时以小于1N·m的均方根扭矩潜移默化地抵抗膝关节屈曲。利用致动器的远程位置，用户在膝盖上体验到的质量仅为1.2公斤。我们发现，在中风患者的步态中，该装置能够增加膝关节的最大屈曲角度和速度。因此，SERKA是一种有效的实验设备，可以选择性地改变中风后膝关节的运动学和步态。
Many of those who survive a stroke develop a gait disability known as stiff-knee gait (SKG). Characterized by reduced knee flexion angle during swing, people with SKG walk with poor energy efficiency and asymmetry due to the compensatory mechanisms required to clear the foot. Previous modeling studies have shown that knee flexion activity directly before the foot leaves the ground, and this should result in improved knee flexion angle during swing. The goal of this research is to physically test this hypothesis using robotic intervention. We developed a device that is capable of assisting knee flexion torque before swing but feels imperceptible (transparent) for the rest of the gait cycle. This device uses sheathed Bowden cable to control the deflection of a compliant torsional spring in a configuration known as a Series Elastic Remote Knee Actuator (SERKA). In this investigation, we describe the design and evaluation of SERKA, which includes a pilot experiment on stroke subjects. SERKA could supply a substantial torque (12 N· m) in less than 20 ms, with a maximum torque of 41 N·m. The device resisted knee flexion imperceptibly when desired, at less than 1 N·m rms torque during normal gait. With the remote location of the actuator, the user experiences a mass of only 1.2 kg on the knee. We found that the device was capable of increasing both peak knee flexion angle and velocity during gait in stroke subjects. Thus, the SERKA is a valid experimental device that selectively alters knee kinetics and kinematics in gait after stroke.