From Waves to Touch: Advancing Ultrasound Haptics through Novel Modulation

Abstract

Ultrasound-based mid-air contactless haptics have been an increasingly popular area of development in the past decade for their highly valuable applications in VR environments, automobile safety systems, surgical training environments, and public displays. While currently applied modulation techniques such as amplitude- and spatiotemporal-modulation (AM and STM) can elicit sensations in the human skin for 2D shapes, there is still much to be desired in terms of spatial precision for high-speed scanning points. Specifically, when points are scanned across the human palm at speeds greater than the shear speed of sound, a trailing Mach cone is produced behind the focal point, leading to poor localization and inaccurate shape perception. In this work, time-domain acoustic simulations of an approximate elastic skin model are used to i) characterize a pre-existing modulation technique termed AM-STM and display its increased localization capabilities in comparison to the other preexisting methods, and ii) introduce and define a new modulation technique termed SM-STM which has displayed further increased localization and improved perception.