Wearable Electrohydraulic Actuation For Salient Full‐Fingertip Haptic Feedback

Abstract Although essential for an immersive experience in extended reality (XR), providing salient and versatile touch feedback remains a technical challenge. Existing solutions restrict hand movements with bulky rigid structures, require a tethered energy source to power actuators worn on the hand, or output vibrations that lack expressiveness. This study introduces a design strategy for compact, lightweight, untethered haptic feedback centering on a 30‐µm‐thick inflatable chamber that naturally conforms to the fingertip; to minimize fluidic losses and enable high bandwidth, a soft electrohydraulic pump mounted on the hand actuates the chamber via a mechanically transparent fluidic channel. A 15.2‐mm‐diameter prototypical actuation chamber achieves 8 N peak force, 3 N steady‐state force, stroke up to 5 mm, and bandwidth from 0 to 500 Hz. In contrast to these salient fingertip cues, the entire hydraulic system has a weight less than 8 g and a thickness less than 2 mm. Additionally, this study presents a validation approach that uses a commercial fingertip sensor to confirm that the haptic feedback created by the device imitates the touch signals generated during typical hand interactions. Together, this design strategy and validation method can enable a broad spectrum of haptic activities in diverse XR applications, including medical training, online shopping, and social interactions.