Formulation of tactile Gestalt inducing the comfortableness towards development of haptic device

Abstract

To improve the tactile VR technology, we researched the haptic device technology that can provide the material feeling to the palm of hand. We adopted Velvet Hand Illusion (VHI), which is one of the tactile illusion phenomena, and tried to control this sensation. Since it is necessary to create the model of VHI mechanism, we tried to formulate it by applying law of pragnanz in Gestalt theory, which is famous for visual research, to VHI. In the formulation, we focused on the basic VHI stimulus in which two parallel lines (wires) reciprocated between the palms and formulated the VHI intensity by using the phase difference of two parallel lines movement and the speed difference of the two lines as explanatory variables. We conducted the psychophysical experiment and verified this formulation. It was found that our proposed model can explain the relationship between VHI intensity and the stimulus conditions when there was no velocity difference between the two lines. On the other hand, in the condition that included phase and velocity difference, our model explained the relationship between them in only large velocity difference condition. This result suggests that the phase difference and the velocity difference are interrelated, and we should clarify the relationship between them to improve the prediction accuracy of VHI in the future.