Korea Institute of Science and Technology (KIST), Center for Intelligent and Interactive Robotics, Seoul, 02792, Korea.
Department of Mechanical Engineering, Korea University, Seoul, 02841, Korea.
Sci Rep. 2021 Sep 23;11(1):18954. doi: 10.1038/s41598-021-98589-2.
As touch screen technologies advanced, a digital stylus has become one of the essential accessories for a smart device. However, most of the digital styluses so far provide limited tactile feedback to a user. Therefore we focused on the limitation and noted the potential that a digital stylus may offer the sensation of realistic interaction with virtual environments on a touch screen using a 2.5D haptic system. Thus, we developed a haptic stylus with SMA (Shape Memory Alloy) and a 2.5D haptic rendering algorithm to provide lateral skin-stretch feedback to mimic the interaction force between fingertip and a stylus probing over a bumpy surface. We conducted two psychophysical experiments to evaluate the effect of 2.5D haptic feedback on the perception of virtual object geometry. Experiment 1 investigated the human perception of virtual bump size felt via the proposed lateral skin-stretch stylus and a vibrotactile stylus as reference. Experiment 2 tested the participants' ability to count the number of virtual bumps rendered via the two types of haptic styluses. The results of Experiment 1 indicate that the participants felt the size of virtual bumps rendered with lateral skin-stretch stylus significantly sensitively than the vibrotactile stylus. Similarly, the participants counted the number of virtual bumps rendered with the lateral skin-stretch stylus significantly better than with the vibrotactile stylus. A common result of the two experiments is a significantly longer mean trial time for the skin-stretch stylus than the vibrotactile stylus.
随着触摸屏技术的进步，数字手写笔已成为智能设备的必备配件之一。然而，迄今为止，大多数数字手写笔为用户提供的触觉反馈非常有限。因此，我们专注于这一限制，并认识到数字手写笔可能通过使用 2.5D 触觉系统为用户提供在触摸屏上与虚拟环境进行真实交互的感觉的潜力。因此，我们开发了一种带有 SMA（形状记忆合金）的触觉手写笔和一种 2.5D 触觉渲染算法，以提供侧向皮肤拉伸反馈，模拟指尖和探针在凹凸不平的表面上的交互力。我们进行了两项心理物理实验，以评估 2.5D 触觉反馈对虚拟对象几何形状感知的影响。实验 1 研究了通过提出的侧向皮肤拉伸手写笔和作为参考的振动触觉手写笔感知虚拟凸起大小的人类感知。实验 2 测试了参与者通过两种类型的触觉手写笔数出虚拟凸起数量的能力。实验 1 的结果表明，与振动触觉手写笔相比，参与者明显更敏感地感觉到通过侧向皮肤拉伸手写笔呈现的虚拟凸起的大小。同样，参与者通过侧向皮肤拉伸手写笔数出的虚拟凸起数量明显优于振动触觉手写笔。这两个实验的一个共同结果是，皮肤拉伸手写笔的平均试验时间明显长于振动触觉手写笔。
