The passive stiffness of the wrist and forearm
The passive stiffness of the wrist and forearm
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DOI：
10.1152/jn.01014.2011
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发表时间：
2012-08-01
影响因子：
2.5
通讯作者：
Krebs, Hermano I.
中科院分区：
文献类型：
--
作者：
Formica, Domenico;Charles, Steven K.;Krebs, Hermano I.
Formica D, Charles SK, Zollo L, Guglielmelli E, Hogan N, Krebs HI。手腕和前臂的被动僵硬。中国生物医学工程学报（英文版）。2012年5月30日首次发表；doi: 10.1152 / jn.01014.2011。-因为手腕旋转动力学是由刚度主导的（Charles SK, Hogan N. J Biomech 44: 614-621, 2011），了解人类如何计划和执行协调的手腕旋转需要了解手腕关节的刚度特征。过去，手腕关节的被动刚度以1个自由度（DOF）来测量。虽然这些1-DOF测量告诉我们神经肌肉系统必须克服的动力学才能在纯粹的屈伸（FE）或纯粹的桡尺偏差（RUD）中旋转手腕，但手腕很少在纯粹的FE或RUD中旋转。相反，理解自然的手腕旋转需要了解结合FE和RUD的手腕刚度。本报告的目的是在FE和RUD跨越的整个空间中提供被动手腕刚度的测量。使用为手腕和前臂设计的康复机器人，我们测量了10名受试者在FE， RUD和组合中手腕关节的被动刚度。为了比较，我们也测量了前臂的被动僵硬度（旋前-旋后）。我们对纯FE和RUD的测量结果与之前的1自由度测量结果一致。我们已经线性化了2自由度刚度测量，并以刚度椭圆的形式和刚度矩阵的形式表示它们，这对腕部旋转动力学建模很有用。我们发现被动腕关节刚度是各向异性的，RUD组的刚度大于FE组。我们还发现被动腕部僵硬与腕部解剖轴不一致；相对于有限元和RUD轴，刚度椭圆的长轴和短轴旋转了类似20度。最小僵硬度的方向在尺屈曲和桡侧伸展之间，这是许多自然运动（称为“投掷飞镖的运动”）中使用的方向，这表明神经系统可能利用最小僵硬度的方向进行常见的手腕旋转。
Formica D, Charles SK, Zollo L, Guglielmelli E, Hogan N, Krebs HI. The passive stiffness of the wrist and forearm. J Neurophysiol 108: 1158-1166, 2012. First published May 30, 2012; doi:10.1152/jn.01014.2011.-Because wrist rotation dynamics are dominated by stiffness (Charles SK, Hogan N. J Biomech 44: 614-621, 2011), understanding how humans plan and execute coordinated wrist rotations requires knowledge of the stiffness characteristics of the wrist joint. In the past, the passive stiffness of the wrist joint has been measured in 1 degree of freedom (DOF). Although these 1-DOF measurements inform us of the dynamics the neuromuscular system must overcome to rotate the wrist in pure flexion-extension (FE) or pure radial-ulnar deviation (RUD), the wrist rarely rotates in pure FE or RUD. Instead, understanding natural wrist rotations requires knowledge of wrist stiffness in combinations of FE and RUD. The purpose of this report is to present measurements of passive wrist stiffness throughout the space spanned by FE and RUD. Using a rehabilitation robot designed for the wrist and forearm, we measured the passive stiffness of the wrist joint in 10 subjects in FE, RUD, and combinations. For comparison, we measured the passive stiffness of the forearm (in pronation-supination), as well. Our measurements in pure FE and RUD agreed well with previous 1-DOF measurements. We have linearized the 2-DOF stiffness measurements and present them in the form of stiffness ellipses and as stiffness matrices useful for modeling wrist rotation dynamics. We found that passive wrist stiffness was anisotropic, with greater stiffness in RUD than in FE. We also found that passive wrist stiffness did not align with the anatomical axes of the wrist; the major and minor axes of the stiffness ellipse were rotated with respect to the FE and RUD axes by similar to 20 degrees. The direction of least stiffness was between ulnar flexion and radial extension, a direction used in many natural movements (known as the "dart-thrower's motion"), suggesting that the nervous system may take advantage of the direction of least stiffness for common wrist rotations.