Effect of skin hydration on the dynamics of fingertip gripping contact
Effect of skin hydration on the dynamics of fingertip gripping contact
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DOI：
10.1098/rsif.2011.0086
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发表时间：
2011-11-07
影响因子：
3.9
通讯作者：
Thonnard, J. -L.
中科院分区：
文献类型：
--
作者：
Andre, T.;Levesque, V.;Thonnard, J. -L.
指尖接触的动态表现在复杂的皮肤运动中，观察到从粘滞状态到完全发展的滑动。在研究这种转变时，我们发现它取决于皮肤的水合作用。为了量化这种依赖性，我们要求受试者在玻璃表面滑动他们的食指，同时在视觉反馈的帮助下保持相互作用力的法向分量不变。使用光学仪器对接触区域内的皮肤变形进行成像，使我们能够量化滑动和粘附区域的相对大小。当切向力分量从0增加到最大值时，粘皮面积与总接触面积之比从1线性减小到0。该关系的斜率与法向力分量呈负相关。皮肤水合水平显著影响包封接触从粘着到滑动的动力学过程。具体效果是减少接触滑动的趋势，而不考虑摩擦系数的变化。由于在干燥的皮肤条件下握力更不稳定，我们的研究结果表明，神经系统对干燥皮肤的反应是握力过大，这不能简单地用摩擦系数的变化来解释。
The dynamics of fingertip contact manifest themselves in the complex skin movements observed during the transition from a stuck state to a fully developed slip. While investigating this transition, we found that it depended on skin hydration. To quantify this dependency, we asked subjects to slide their index fingertip on a glass surface while keeping the normal component of the interaction force constant with the help of visual feedback. Skin deformation inside the contact region was imaged with an optical apparatus that allowed us to quantify the relative sizes of the slipping and sticking regions. The ratio of the stuck skin area to the total contact area decreased linearly from 1 to 0 when the tangential force component increased from 0 to a maximum. The slope of this relationship was inversely correlated to the normal force component. The skin hydration level dramatically affected the dynamics of the contact encapsulated in the course of evolution from sticking to slipping. The specific effect was to reduce the tendency of a contact to slip, regardless of the variations of the coefficient of friction. Since grips were more unstable under dry skin conditions, our results suggest that the nervous system responds to dry skin by exaggerated grip forces that cannot be simply explained by a change in the coefficient of friction.