Programmability of ultrathin metasurfaces through curvature

Stimulation is an integral part of any human-machine interface such as wearable devices. Recently, an approach based on vibro-tactile communication through metasurfaces has been introduced, where a grid of geometric patterns can induce targeted sensations on the human skin, amplifying both input force and displacement, upon contact. The previous work only considered flat metasurfaces covering a small region of the human skin. However, for practical applications, human curvature and its effects on operational frequencies should be considered. In this paper, we study the different factors that can affect the operational effectiveness of metasurfaces as versatile human-machine interface. We consider three main factors (1) the effect of periodicity (i.e., the repetition of the same pixel over an extended region in space to cover a large area), (2) the effect of curvature, and (3) the variations in geometry and fabrication tolerances on the operational frequencies of the metasurfaces. Our analyses shed light on some of the factors that can affect the design and performance of metasurfaces as haptic interfaces and could prove crucial in adopting such technology in future applications such as soft robotics, wearable devices, and human-machine-interaction interfaces. (C) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This paper studies the key factors of metasurfaces as human-machine interfaces, including the effects of periodicity, curvature, and geometric parameters on operational frequencies. The research results are crucial for the adoption of metasurface technology in future applications such as soft robotics, wearable devices, and human-machine interaction interfaces.