Virtual tactile texture using electrostatic friction display for natural materials: The role of low and high frequency textural stimuli

As touchscreens have become a standard feature in mobile devices, technologies for presenting tactile texture feedback on the panel have been attracting attention. We tested a new method for presenting natural materials using an electrostatic tactile texture display. In this method, the frictional forces are decomposed into low- and high-frequency components. The low-frequency component was modeled based on Coulomb’s friction law, such that the friction force was reactive to the finger’s normal force. The high-frequency component was modeled using an auto-regressive model to retain its features of frequency spectra. Four natural material types, representing leather, cork, denim, and drawing paper, were presented to six assessors using this method. In a condition where only the low-frequency friction force components were rendered, the materials were correctly recognized at 70%. In contrast, when the high-frequency components were superposed, this rate increased to 80%, although the difference was not statistically significant. Our approach to combine a physical friction model and frequency spectrum for low- and high-frequency components, respectively, allows people to recognize virtual natural materials rendered on touch panels.