Improvement of precision grasping performance by interaction between soft finger pulp and hard nail
Improvement of precision grasping performance by interaction between soft finger pulp and hard nail
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通过软指腹与硬指甲的相互作用提高精确抓取性能
DOI：
10.1089/soro.2021.0231
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发表时间：
2023
期刊：
影响因子：
7.9
通讯作者：
Shunta Togo
中科院分区：
文献类型：
--
作者：
Ayane Kumagai;Yoshinobu Obata;Yoshiko Yabuki;Yinlai Jiang;Hiroshi Yokoi;Shunta Togo
在这项研究中，我们研究了指甲的存在或不存在对使用人工拟人手指精确抓取的影响。我们假设指甲通过增加摩擦系数同时抑制指尖变形来提高精确抓握性能。为了验证我们的假设，我们开发了人工指尖，每一个都由骨头，指甲，皮肤和软组织组成，并制作了三种类型的人工手指，不同的皮肤柔软度等级和人工手指无指甲作为控制条件。利用所研制的人工指尖对圆柱形物体和T形块进行了拔出实验，并比较了有、无指甲人工指尖的夹持力大小。指甲有助于物体抓持稳定性，因为在具有柔软皮肤的人造指尖中存在指甲显著增加了抓持力的大小。与圆柱形物体（最大1.08倍）相比，T形块的保持力的大小的增加率更显著（最大3.10倍），这是因为指腹变形被指甲抑制，并且对于抓握物体形成了形状闭合，即几何约束。研究结果表明，软指尖和硬指甲可以显著提高机器人软手的抓取性能。这些结果表明，人指甲通过对被抓物体形成几何约束，抑制指腹变形，提高了精确抓取性能。
In this study, we investigated the effect of the presence or absence of fingernails on precision grasping using artificial anthropomimetic fingers. We hypothesized that fingernails improve precision grasping performance by increasing the friction coefficient while suppressing fingertip deformation. To test our hypothesis, we developed artificial fingertips, each composed of bone, nail, skin, and soft tissue, and fabricated three types of artificial fingers with different skin softness grades and artificial fingers without nails as the control condition. Pullout experiments of cylindrical objects and T-shaped blocks were conducted using the developed artificial fingertips with and without nails, and the magnitude of the holding force was compared. The nail contributed to object grasping stability because the magnitude of the holding force was significantly increased by the presence of the nail in the artificial fingertip with soft skin. The rate of increase in the magnitude of the holding force of the T-shaped block was more significant (3.10 times maximum) compared with the cylindrical object (1.08 times maximum) because the finger pulp deformation was suppressed by the nail, and the form closure, that is, geometric constraint, was formed for the grasping object. The results of this study show that soft fingertips and hard nails can significantly improve the grasping performance of soft robotic hands. And these results suggest that the human nail improves precision grasping performance by forming geometric constraints on the grasped object, suppressing finger pulp deformation.