Design and Evaluation of a Soft Hydro-Pneumatic Haptic Ring for Multimodal Texture Rendering

Abstract

With the growing popularity of virtual and augmented reality, there is an increasing demand for haptic devices that can replicate naturally occurring tactile sensations. Specifically, multimodal devices capable of delivering multiple types of haptic feedback simultaneously are crucial for enhancing realism and immersion. In this paper, we introduce a novel, entirely soft, multimodal haptic ring designed to provide vibratory, pressure, and thermal stimuli. Our ring, targeted for texture rendering applications, integrates pneumatic and hydraulic circuits to accurately simulate the roughness, temperature, and compliance cues experienced when freely exploring surfaces with the fingertip. We validated the performance of our system through a psychophysical experiment, which demonstrated that participants could match virtual textures displayed by the ring with real textures with up to 90 % accuracy for several surfaces. Participant’s adjectives ratings indicated that the ring can provide distinctly different stimuli in all of the rendered perceptual dimensions, closely matching those of real textures. This study shows that by relocating tactile feedback from the fingertip, our ring offers maximum wearability, enabling free exploration of surrounding environments and full range of motion, highlighting its potential in mixed reality applications.