Tactile Rendering Using Three Basic Stimulus Components in Ultrasound Midair Haptics

TL;DR

This paper introduces a method to render tactile textures in ultrasound midair haptics by combining static pressure and vibration stimuli, enabling perception of various textures like smoothness and roughness without contact.

Contribution

It proposes a novel approach to synthesize tactile textures in ultrasound midair haptics by combining three basic stimuli, enhancing the realism of non-contact tactile feedback.

Findings

At least six discriminable textures were rendered.

Pressure-only stimuli perceived as slippery and smooth.

Vibration stimuli increased perceived roughness to sandpaper level.

Abstract

Ultrasound midair haptics (UMH) can present non-contact tactile stimuli using focused ultrasound without any wearables. Recently, UMH has been shown to present not only conventional vibration stimulus but also static pressure stimulus by locally rotating an ultrasound focus at several hertz. Current UMH can present three basic tactile stimuli: static pressure, 30 Hz vibration, and 150 Hz vibration. These primarily elicit responses from three distinct types of mechanoreceptors: SA-I, FA-I, and FA-II. As human texture perception relies on the combination of mechanoreceptor neural responses, this study proposes combining the three basic stimuli to render tactile texture in UMH. Experimental results demonstrate that the proposed method can render at least six discriminable textures with different roughness and friction sensations. Notably, through comparisons with real physical objects, we found that the pressure-only stimulus was perceived as slippery and smooth. The smoothness was similar to a glass marble. When vibration stimuli were synthesized, the perceived roughness and friction increased significantly. The roughness level reached that of a 100-grit sandpaper.