LoopBot: Representing Continuous Haptics of Grounded Objects in Room-scale VR

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DOI

In room-scale virtual reality, providing continuous haptic feedback from touching grounded objects, such as walls and handrails, has been challenging due to the user's walking range and the required force. In this study, we propose LoopBot, a novel technique to provide continuous haptic feedback from grounded objects using only a single user-following robot. Specifically, LoopBot is equipped with a loop-shaped haptic prop attached to an omnidirectional robot that scrolls to cancel out the robot's displacement, giving the user the haptic sensation that the prop is actually fixed in place, or ``grounded.'' We first introduce the interaction design space of LoopBot and, as one of its promising interaction scenarios, implement a prototype for the experience of walking while grasping handrails. A performance evaluation shows that scrolling the prop cancels $77.5\%$ of the robot's running speed on average. A preliminary user test ($N=10$) also shows that the subjective realism of the experience and the sense of the virtual handrails being grounded were significantly higher than when the prop was not scrolled. Based on these findings, we discuss possible further development of LoopBot.