RoboHaptics: Designing Haptic Interactions for Lower Body with Quadruped Robot Dogs

Extended Reality (XR) systems now offer high-quality visual and auditory immersion, yet their support for haptic feedback remains uneven, especially for the legs and feet. Many VR experiences visually depict lower-body events such as impacts, boundaries, and guidance, but provide little or no corresponding physical sensation. This thesis investigates whether a commercially available quadruped robot can be treated as a mobile, off-body “lower-body haptic instrument” rather than solely as a locomotion platform. We introduce RoboHaptics, a haptic toolkit that turns quadruped motion into programmable haptic prim-itives for the lower body. RoboHaptics abstracts low-level control into six parameterized primitives—Knock, Tap, Double Tap, Touch, Press, and Push—which can be configured by robot posture, approach trajectory, contact footprint, and target body location. Two technical studies characterize the capability envelope of these primitives. A load-cell experiment shows that different postures can safely deliver approximately 3–28 N of contact forces, within ranges suitable for repeated lower-body stimulation. A mannequin-based experi-ment quantifies reachability around the legs and demonstrates millimetre-scale precision and accuracy across common targets, confirming that the quadruped can reliably “hit” intended locations. Building on this characterization, two user studies investigate how quadruped-mediated lower-body hap-tics are experienced and interpreted. In VR scenarios such as a fence, a rolling ball, and a table edge, participants rated the comfort, realism, and immersion of RoboHaptics feedback in comparison to ground-truth physical proxies. A second study probes the six primitives as a tactile vocabulary, revealing consistent mappings from temporal–force profiles to social meanings including alerts, boundaries, assistance, and re-assurance. Together, this thesis establishes quadruped robots as a viable lower-body haptic instrument for XR, contributing a design space, authoring toolkit, empirical characterization, and design guidelines that connect robot movement choices to perceived safety, legibility, and immersion.