Inoue Koki, Okamoto Shogo, Akiyama Yasuhiro, Yamada Yoji
IEEE Trans Haptics. 2020 Jan-Mar;13(1):123-129. doi: 10.1109/TOH.2020.2966704. Epub 2020 Jan 14.
Understanding the tribological phenomena when fingers slide over soft surfaces such as skin is important for many practical applications. Therefore, this article analyzed the coefficients of friction for a bare finger sliding over artificial skin with different hardness under dry and lubricated surface conditions. This article contrasts with previous research that predominantly analyzed the contact between skin and hard surfaces or probes. Under dry conditions, the coefficient of friction was constant for artificial skins that were harder than the finger pad, irrespective of the normal force of the finger. However, the coefficient of friction decreased with increasing normal force for softer artificial skins. When the surface of the artificial skin model was lubricated with mica, the coefficient of friction exhibited normal-force dependence only for soft artificial skins, similar to the observations under dry conditions. This effect was due to the deformation friction; thus, the coefficient of friction increased as the normal force increased. Conversely, when the model was lubricated with TiO, the coefficient of friction depended on the normal force for all hardness levels. These findings provide insights into the friction experienced during skin-skin or skin-soft material contact under dry and lubricated conditions that can easily occur in daily life. Thus, the results of this study can be useful for the development of skin care products or assistive robots involving human-robot contact.
了解手指在皮肤等柔软表面滑动时的摩擦学现象对许多实际应用都很重要。因此，本文分析了裸手指在不同硬度的人造皮肤上于干燥和润滑表面条件下滑动时的摩擦系数。本文与以往主要分析皮肤与硬表面或探针之间接触的研究形成对比。在干燥条件下，对于比指垫硬的人造皮肤，摩擦系数是恒定的，与手指的法向力无关。然而，对于较软的人造皮肤，摩擦系数随法向力的增加而降低。当用人造皮肤模型表面用云母润滑时，摩擦系数仅在软人造皮肤上表现出法向力依赖性，这与干燥条件下的观察结果相似。这种效应是由于变形摩擦；因此，摩擦系数随着法向力的增加而增加。相反，当模型用二氧化钛润滑时，摩擦系数在所有硬度水平下都依赖于法向力。这些发现为日常生活中容易出现的干燥和润滑条件下皮肤与皮肤或皮肤与软材料接触时的摩擦提供了见解。因此，本研究结果可用于护肤品或涉及人机接触的辅助机器人的开发。
