A Robust Approach for Reproducing the Haptic Sensation of Sandpaper With Different Roughness During Bare Fingertip Interaction

Jianyao Zhang,Hiroyuki Kajimoto

doi:10.3389/frvir.2022.829946

Jianyao Zhang, Hiroyuki Kajimoto

Open Access

https://doi.org/10.3389/frvir.2022.829946

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Abstract

When reproducing realistic virtual textures for bare finger interaction, an accelerometer attached to a fingernail is commonly used. This measurement depends on the dynamic conditions during the exploration action, and slight differences in roughness are difficult to acquire accurately because of masking by shivering, low-pass filtering by the finger tissue, and sensor accuracy. We propose a simpler yet robust approach based on the 3D measurement of the surface and compare it with the conventional approach. The 3D surface images of sandpaper with different degrees of roughness were captured using a 3D microscope, and the line roughness curve was transformed into an acceleration curve by quadratic differential transformation. The real-time acceleration and frictional force were measured by an accelerometer and force sensor for comparison. A haptic device replaying acceleration-based vibrations by two audio speakers and producing tangential force by a motor-controlled liner slide was developed for reproduction. We conducted experiments with participants to evaluate the reproduction approach. Experimental results showed that the conventional approach obtained sufficient discriminability with the assistance of force, whereas the proposed approach achieved higher reproducibility and discriminability by sole vibration. Thus, our approach provides a new reference for studies of bare finger interaction with rough surfaces.

Highlights

IntroductionWith the rapid development of computer graphics technologies, it has become possible to construct 3D models in which virtual objects have texture details that are visually almost indistinguishable from those of real objects
The acceleration-based vibration signal is obtained by quadratic differential transformation of the line roughness curve in the image and is processed by an audio processing software to reproduce the textures of different sandpapers
When the sandpaper became smoother, the score of the same reproduced texture showed an increasing trend, which indicates that the perception of the roughness of the same reproduced texture did not change despite the change in the benchmark

Summary

Introduction

With the rapid development of computer graphics technologies, it has become possible to construct 3D models in which virtual objects have texture details that are visually almost indistinguishable from those of real objects This allows computers to build a virtual environment that can achieve a high degree of similarity with the real environment. Graphic rendering can achieve high precision for surface textures, the haptic sensation has not yet been reproduced to a degree close to the precision of visual reproduction. To achieve such high-quality haptic reproduction, a robust approach is needed to accurately capture the slight differences in the texture of a specific material and reproduce them as distinguishable. Experimental results revealed that the conventional approach obtains sufficient discriminability with the assistance of force, whereas the proposed approach achieves higher reproducibility and discriminability by vibration only

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