Identification of danger state for grasping delicate tofu with fingertips containing viscoelastic fluid
Identification of danger state for grasping delicate tofu with fingertips containing viscoelastic fluid
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含有粘弹性液体的指尖抓取嫩豆腐的危险状态识别
DOI：
10.1109/iros.2015.7353418
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Tetsuyou Watanabe
中科院分区：
文献类型：
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作者：
R. Adachi;Yoshinori Fujihira;Tetsuyou Watanabe
在这项研究中，我们实验研究的过程中，导致断裂豆腐抓变形指尖充满流体。在我们以前的论文[1，2]中，我们使用充满粘弹性流体的橡胶袋开发了可变形的指尖，并提出了一种在没有任何关于断裂的预先知识的情况下抓取精致豆腐的策略。然而，预测点接近断裂，当时的预测仍然是一场赌博。为了实现断裂预测的早期阶段，我们检查的过程中，导致断裂时，推动豆腐的变形指尖。指尖的硬度可以通过指尖内的流体压力来控制。对指尖不同硬度水平的推力和流体压力进行了检查。主要结论和贡献如下。1)接触力与流体压力之比的收敛给出了凹痕发生的指示。当指尖橡胶袋未填充（低刚度）时，可以看到这种收敛。2)指尖橡胶袋未填充时比填充时更容易发生凹痕（高刚度）。3)反复观察随着豆腐被推动流体压力增加速率的变化。我们将其定义为相变，并提出了一种检测这种变化的方法。通过比较不同近似模型的拟合精度，确定相变点。4)通过检测第一个相变（如果指尖袋未完全填充，则在接触力与流体压力的比率收敛之后），检测断裂前的最后一个相变和倒数第二个相变。检测到的点可以被认为是指示不靠近断裂点的断裂风险的警报点。
In this study, we experimentally investigated the process leading to fracture in tofu grasping by deformable fingertips filled with a fluid. In our previous papers [1, 2], we developed deformable fingertips using a rubber bag filled with a viscoelastic fluid, and presented a strategy for delicate tofu grasping without any advance knowledge about fracture. However, the predication point was close to fracture, and the prediction was then still a gamble. In order to realize fracture prediction at an earlier stage, we examined the process leading to fracture when pushing tofu by the deformable fingertips. The stiffness of the fingertips can be controlled with the pressure of the fluid inside the fingertips. The pushing force and fluid pressure were examined for different levels of stiffness of the fingertips. The main findings and contributions are as follows. 1) The convergence of the ratio of the contact force to fluid pressure gives an indication of dent occurrence. This convergence could be seen when fingertip rubber bag was not filled (low stiffness). 2) It was easier for a dent to occur when the fingertip rubber bag was not filled than when it was filled (high stiffness). 3) Changes in the rate of increase of the fluid pressure as the tofu was pushed were repeatedly observed. We defined this as a phase change and present a method for detecting such changes. The phase change points were detected by comparing the fitting accuracies of different approximation models. 4) The last and second to the last phase changes before fracture were detected by detecting the first phase change (after the convergence of the rate of the contact force to fluid pressure if the fingertip bag was not completely filled). The detected points can be regarded as alert points indicating a fracture risk that is not close to the fracture point.