IEEE Trans Haptics. 2020 Apr-Jun;13(2):425-435. doi: 10.1109/TOH.2019.2954882. Epub 2019 Nov 21.
Making a virtual object shape recognizable using a haptic display is one of the major themes of haptic research. In previous works, multipoint haptic displays have been developed that had a high contact point density between the users' finger skin and the virtual object. However, the ideal contact point density that enables intuitive shape recognition has not been determined yet. Meanwhile, there is also a fundamental problem; that is, real fingers and virtual objects do penetrate, which cannot be solved with such wearable displays. This article investigated the influence of both contact point density and penetration on the shape recognition performance. We prepared a real testing environment where the user touched the real object, and where we could simulate both the sparse contact point and the penetration. Specifically, users' fingers wore thin film coated with glass particles and they touched the urethane foams that deformed flexibly. The result of experiments showed a broad trend where the sparseness of the contact and the softness of the object influenced the exploration time required to achieve recognition. In addition, the result suggested that the larger contact density could make up for the problem of penetration. We confirmed it by conducting two different tasks: (1) exploring the object surface with the index finger and (2) grasping the object surface with the thumb and the index finger.
使用力反馈显示器使虚拟对象的形状可识别是力反馈研究的主要主题之一。在以前的工作中，已经开发出具有用户手指皮肤和虚拟对象之间高接触点密度的多点力反馈显示器。然而，能够实现直观形状识别的理想接触点密度尚未确定。同时，还存在一个根本问题，即真实手指和虚拟对象确实会穿透，这是无法通过这种可穿戴显示器解决的。本文研究了接触点密度和穿透对形状识别性能的影响。我们准备了一个真实的测试环境，用户在该环境中触摸真实物体，并且我们可以模拟稀疏的接触点和穿透。具体来说，用户的手指戴着涂有玻璃颗粒的薄膜，并触摸可灵活变形的聚氨酯泡沫。实验结果显示出一种广泛的趋势，即接触的稀疏和物体的柔软度会影响实现识别所需的探索时间。此外，结果表明更大的接触密度可以弥补穿透的问题。我们通过进行两项不同的任务来确认这一点：（1）用食指探索物体表面，（2）用拇指和食指抓住物体表面。
