Development of a tactile display for a hand with sensory feedback

如何将触觉反馈给人类，是目前人工手、功能性电刺激、遥存在机器人和虚拟现实等领域的重大课题之一。本研究在心理物理实验的基础上，研究了哪些物理参数与材料质量的识别有关，并提出了一种触觉显示方法，以尽可能正确地将材料质量显示在人的手中。在此基础上，利用金属氢化物合金作动器，设计了一种肘部作用力显示装置。这些显示器的效果是通过将它们连接到带有感觉反馈的机器人手上来评估的。研究结果如下：(1)不同表面粗糙度、不同粘度、不同热容的材料在手指表面显示时，粗糙感在材料表面粒径为30um时由光滑变为粗糙，在粘度为17dPa.s时，粗糙感最粘稠。通过改变手指表面的温度，可以在一定程度上显示材料的质量。(2)手指握住材料时，剪应力感觉的差值范围为20~30微米。差值阈值取决于材料的移动方向，在32度皮肤温度下最低。虚拟材料的重量可以通过将金属氢化物致动器连接到肘部来显示。许多与触觉相关的形容词似乎都是由表面粗糙度、粘度和皮肤温度等参数的组合来表示的。基于本研究的结果，我们正在计划设计一种具有感觉反馈的机械手的触觉显示器。

How the tactile sensation should be fedback to the human is one of the big subjects in the fields of artificial hand, functional electrical stimulation, teleexistence robot and virtual reality. In this study, what kind of physical parameters is related to recognition of material quality was investigated based on psychophysical experiments and a tactile display method was proposed in order to display the material quality to the human hand as properly as possible. Furthermore, a force display to an elbow was designed using an actuator made of metal hydride alloy. The efficacy of these displays was evaluated by attaching them to a robot hand with sensory feedback. The following is summary of research results.(1) When the material with various surface roughness, various viscosity and various heat capacities was displayd on the finger surface, the sensation of roughness was found to change from smooth to rough at 30 um particle size of the material surface and the sensation became the most slimy at the viscosity of 17dPa.s. The quality of material could be displayd some extent by changing the temperature of the finger surface.(2) Differential limen of shear stress sensation was found to be 20 to 30 um when fingers grasped the material. The differential limen depended on the moving direction of the material and it was the lowest at 32 degree skin temperature. The weight of virtual material could be displayd by attaching the metal hydride actuator to an elbow.Many adjectives related to the tactile sensation were seemed to be represented by combination of parameters such as surface roughness, viscosity and skin temperature. We are plannin to design a tactile display for a robot hand with sensory feedback based on the results obtained by this research.