AquaHaptics: Hand-based Multimodal Haptic Interactions for Immersive Virtual Underwater Experience

With the advancement of haptic interfaces, recent studies have focused on enabling detailed haptic experiences in virtual reality (VR), such as fluid-haptic interaction. However, rendering forces from fluid contact often causes a high-cost computation. Given that motion-induced fluid feedback is crucial to the overall experience, we focus on hand-perceivable forces to enhance underwater haptic sensation by achieving high-fidelity rendering while considering human perceptual capabilities. We present a new multimodal (tactile and kinesthetic) haptic rendering pipeline. Here, we employ drag and added mass forces by dynamically adapting to the user's hand movement and posture with pneumatic-based haptic gloves. We defined decaying and damping effects to indicate fluid properties caused by inertia and confirmed their significant perceptual impacts compared to using only physics-based equations in a perception study. By modulating pressure variations, we reproduced fluid smoothness via exponential tactile deflation and light fluid mass via linear kinesthetic feedback. Our pipeline enabled richer and more immersive VR underwater experiences by accounting for precise hand regions and motion diversity.