A User-customized and Untethered Electro-haptic Device for Immersive Human-Machine Interaction

TL;DR

This work tackles the limitations of tethered, low-resolution haptic devices by introducing a palm-worne, ultra-thin electro-haptic system that is per-user customizable from a single hand image. Using printable liquid metal ink and a palm-wide independently-addressable electrode array, the device delivers finely modulated, multi-dimensional tactile cues via waveform parameters, enabling richer VR interactions. A dedicated design algorithm reconstructs a 3D hand model and maps stimulation sites to reach true per-user ergonomic fit, while a compact wrist-worn driver provides safe, constant-current pulses across the electrode network. Across three user studies, the device shows minimal interference with natural movement, supports fine-grained perceptual control, and enhances VR tasks such as timing, grasping, and painting, demonstrating practical impact for immersive AR/VR experiences. The combination of personalization, flexibility, and integrated hardware positions this approach as a scalable, low-cost pathway toward next-generation haptic augmentation in immersive environments.

Abstract

Haptic feedback is essential for human-machine interaction, as it bridges physical and digital experiences and enables immersive engagement with virtual environments. However, current haptic devices are frequently tethered, lack portability and flexibility. They also have limited ability to deliver fine-grained, multi-dimensional feedback. To address these challenges, we present a flexible, ultra-thin, and user-customized electro-haptic device fabricated with soft materials and printable liquid metal ink. Its highly integrated and lightweight design minimizes interference with natural hand movements while maintaining reliable skin contact. By delivering finely controlled electrical stimulation through 15 electrodes, it can evoke a wide range of tactile sensations that cover diverse interaction scenarios. Our user study demonstrates that the device is comfortable to wear and capable of generating tunable, precise electro-haptic feedback, thereby significantly enhancing immersion and realism in human-machine interactions.

Figures (13)

• Figure 1: Schematic diagram illustrating the structure of our electro-haptic device. Simply by capturing an image of the user's hand, an appropriately sized model can be generated and used for device fabrication. Soft materials and printable liquid metal ink are used for flexible design. When interacting with objects in the VR environment, even though users are not physically holding anything in the real world, the electro-haptic device provides them with a realistic haptic sensation, as if they were holding actual objects in their hands.
• Figure 2: Statistical evaluation of the personalized glove design algorithm.Upper: Absolute errors (cm) between predicted and ground-truth finger lengths, shown as boxplots for the five fingers (thumb, forefinger, middle, ring, pinky). The grey line denotes the mean error across fingers. Lower: Relative errors (%) for each finger, further decomposed into four anatomical segments (metacarpal, proximal phalanx, intermediate phalanx, distal phalanx) along with the averaged error.
• Figure 3: Algorithmic pipeline for personalized device design. From left to right: input hand image, algorithm-extracted contour, computed stimulation sites with interconnections, and the fabricated devices applied on the hand. Examples (a–c) show three different users, their personal device show in three different colors for easier recognition.
• Figure 4: Design of printable liquid metal conductive ink. (a) Montmorillonite dispersion. (b) Liquid metal. (c) Printable liquid metal-montmorillonite conductive ink.
• Figure 5: The wrist-worn electro-haptic stimulator. (a) Our wrist-worn electro-haptic stimulator. (b) Schematics of our custom electro-haptic stimulator.