Comparison of wide-band vibrotactile and friction modulation surface gratings
This work addresses haptic feedback design for human-computer interaction, but it is incremental as it builds on existing methods for tactile perception.
This study tackled the problem of comparing virtual gratings produced via vibrotactile and friction modulation to understand perceptual similarity and physical origins, finding that out-of-plane velocity predicts vibrotactile intensity relative to shear forces and showing high perceptual similarity scaling with frequency.
This study seeks to understand conditions under which virtual gratings produced via vibrotaction and friction modulation are perceived as similar and to find physical origins in the results. To accomplish this, we developed two single-axis devices, one based on electroadhesion and one based on out-of-plane vibration. The two devices had identical touch surfaces, and the vibrotactile device used a novel closed-loop controller to achieve precise control of out-of-plane plate displacement under varying load conditions across a wide range of frequencies. A first study measured the perceptual intensity equivalence curve of gratings generated under electroadhesion and vibrotaction across the 20-400Hz frequency range. A second study assessed the perceptual similarity between two forms of skin excitation given the same driving frequency and same perceived intensity. Our results indicate that it is largely the out-of-plane velocity that predicts vibrotactile intensity relative to shear forces generated by friction modulation. A high degree of perceptual similarity between gratings generated through friction modulation and through vibrotaction is apparent and tends to scale with actuation frequency suggesting perceptual indifference to the manner of fingerpad actuation in the upper frequency range.