ETHOS: A Robotic Encountered-Type Haptic Display for Social Interaction in Virtual Reality

ETHOS (Encountered-Type Haptics for On-demand Social interaction) enables corresponding virtual and physical renderings of dynamic interpersonal interactions, demonstrated here with an object handover (left), fist bump (centre), and high five (right). Abstract-- We present ETHOS (Encountered-Type Haptics for On-demand Social interaction), a dynamic encountered-type haptic display (ETHD) that enables natural physical contact in virtual reality (VR) during social interactions such as handovers, fist bumps, and high-fives. The system integrates a torque-controlled robotic manipulator with interchangeable passive props (silicone hand replicas and a baton), marker-based physical-virtual registration via a ChArUco board, and a safety monitor that gates motion based on the user's head and hand pose. We introduce two control strategies: (i) a static mode that presents a stationary prop aligned with its virtual counterpart, consistent with prior ETHD baselines, and (ii) a dynamic mode that continuously updates prop position by exponentially blending an initial mid-point trajectory with real-time hand tracking, generating a unique contact point for each interaction. Bench tests show static colocation accuracy of 5.09 0.94 mm, while user interactions achieved temporal alignment with an average contact latency of 28.58 31.21 These results demonstrate the feasibility of recreating socially meaningful haptics in VR. By incorporating essential safety and control mechanisms, ETHOS establishes a practical foundation for high-fidelity, dynamic interpersonal interactions in virtual environments. I. INTRODUCTION Virtual reality (VR) enables embodied engagement with digital environments and creates immersive experiences that unlock novel affordances. Advances in hardware and content creation over the past decade have driven increasing interest in the field, supporting the adoption of VR across a broad range of domains.