2019 Volume 13 Issue 3 Pages JAMDSM0051
In haptic virtual reality (VR), there are two important challenges: one is the difficulty of reproducing a surface feeling with haptic devices, and the other is the presentation method used for the display. We developed a tactile mouse using palm presentation for the former challenge to tackle the issue, “which tactile perception is superior for texture recognition, active or passive touch?” In a psychophysical experiment, two oblique edges of dot-patterns are presented consecutively as simple textures, and human subjects compare them to determine which is larger. We evaluated the precision of perception using the difference threshold of the edge angles calculated by the constant stimuli method. Experimental results show that the perception precision at low edge movement speeds (45 and 90 mm/s) was higher than that at high speeds (130 and 170 mm/s), and moreover, that there was no significant difference in precision of the edge angle perception between active and passive touches. The former finding seems to be caused by how well the mechanoreceptive unit handles uneven surfaces. The latter finding is due to the mechanism of the efference copy of a motor signal provided from the motor cortex not having a significant influence on texture recognition. The tactile image deterioration induced by the object movement might be compensated for with information processing in the central nervous system, which keeps stable tactile image without help from the efference copy. This work contributes to developing the haptic device which provides visually impaired persons with the tactile map.
