Can stiffness sensations be rendered in virtual reality using mid-air ultrasound haptic technologies?

Abstract

Mid-air haptics technologies convey haptic sensations without any direct contact between the user and the interface. A popular example of this technology is focused ultrasound. It works by modulating the phase of an array of ultrasound emitters so as to generate focused points of oscillating high pressure, which in turn elicit haptic sensations on the user’s skin. Whilst using focused ultrasound to convey haptic sensations is becoming increasingly popular in Virtual Reality (VR), few studies have been conducted into understanding how to render virtual object properties. In this paper, we evaluate the capability of focused ultrasound arrays to simulate varying stiffness sensations in VR. We carry out a user study enrolling 20 participants, showing that focused ultrasound haptics can well provide the sensation of interacting with objects of different stiffnesses. Finally, we propose four representative VR use cases to show the potential of rendering stiffness sensations using this mid-air haptics.