Rachel Kim

Haptic feedback has been employed to enhance shape perception during grasp interactions, improving immersion and task performance in extended reality (XR). Although wearable devices offer precise multi-phalangeal haptic feedback, their bulkiness and complexity often hinder practicality. In addition, fingertip-based tactile feedback often limits users' ability to perceive a continuous and sequential sensation across the finger surfaces during power grasp. We present a haptic shape rendering method that synchronizes spatiotemporal vibrotactile feedback across multiple phalanges with 1-DOF kinesthetic feedback. Using the funneling illusion and duration-modulated vibration patterns, our approach delivers sequential, continuous sensations along the finger to render various shapes. We also develop a lightweight exoskeleton glove with two dorsal-mounted vibration actuators designed to transmit feedback to the ventral surfaces without obstructing motion. Two perception studies demonstrated consistent shape associations and clear preferences for specific patterns. A VR user-experience study further showed that our method achieved higher ratings for realism, satisfaction, and harmony than prior approaches. These findings offer insights into improving immersive and efficient haptic shape rendering in XR.

We propose a haptic interface, Moving-Press, enabling a pressure-based moving phantom sensation on the user's hand. The moving phantom sensation refers to an illusory perception of a continuous tactile stimulus traversing between two discrete stimulation points. While this phenomenon has been studied in the context of vibrotactile feedback, it remains underexplored in the domain of pressure feedback. As integrating phantom sensation offers a promising approach to simplifying typically bulky pressure devices, employing this phenomenon enables more compact pressure rendering systems. Therefore, we investigated whether pressure movement could be induced using two fixed-positioned actuators by leveraging pressure-based phantom sensation. Our initial perception study validated the occurrence of pressure-based phantom sensations on the hand. Then, we examined how varying the indentation depth of each actuator influences the perceived location, and how the phantom sensation intensity differs from a single pressure stimulus. Finally, we proposed a rack-and-pinion-driven wearable haptic device and conducted a user study to identify an appropriate haptic rendering profile for producing natural pressure movement. The results demonstrated that temporal modulation of indentation depth using the proposed device successfully evokes pressure-based moving phantom sensation.

The emergence of vibrotactile feedback in hand wearables enables immersive virtual reality (VR) experience with whole-hand haptic rendering. However, existing haptic rendering neglects inconsistent sensations caused by hand postures. In our study, we observed that changing hand postures alters the distribution of vibrotactile signals which might degrade one's haptic perception. To address the issues, we present HapticPilot which allows an in-situ haptic experience design for hand wearables in VR. We developed an in-situ authoring system supporting instant haptic design. In the authoring tool, we applied our posture-adaptive haptic rendering algorithm with a novel haptic design abstraction called phantom grid. The algorithm adapts phantom grid to the target posture and incorporates 1D & 2D phantom sensation with a unique actuator arrangement to provide a whole-hand experience. With this method, HapticPilot provides a consistent haptic experience across various hand postures is available. Through measuring perceptual haptic performance and collecting qualitative feedback, we validated the usability of the system. In the end, we demonstrated our system with prospective VR scenarios showing how it enables an intuitive, empowering, and responsive haptic authoring framework.

In this study, we explore the effect of hand posture on haptic experience within the hand. With the wide acceptability of using the hand as an input in the XR, it is important to find out the positive and negative effects of hand postures on the haptic experience. We measured the vibration intensity of the hand using an accelerometer on various hand postures. Our results showed that distinctive hand postures alter the vibrotactile actuator’s tactile feedback across the hand.