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 28.53 +/- 31.21 ms across all interaction and control conditions. 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.

翻译：本文提出ETHOS（按需社交交互的遭遇式触觉技术），这是一种动态遭遇式触觉显示装置，能够在虚拟现实中的社交交互（如物品传递、碰拳和击掌）过程中实现自然的物理接触。该系统集成了扭矩控制机器人操纵器与可互换被动道具（硅胶手部复制件及短棍）、基于ChArUco标记板的物理-虚拟配准，以及根据用户头部和手部姿态控制运动的安全监控模块。我们提出了两种控制策略：（i）静态模式：使道具保持静止并与虚拟对应物对齐，这与现有遭遇式触觉显示基准方法一致；（ii）动态模式：通过将初始中点轨迹与实时手部跟踪数据进行指数混合，持续更新道具位置，为每次交互生成独特的接触点。基准测试显示静态并置精度为5.09 +/- 0.94毫米，而用户交互在所有交互与控制条件下实现了时间对齐，平均接触延迟为28.53 +/- 31.21毫秒。这些结果证明了在虚拟现实中重建具有社交意义的触觉体验的可行性。通过整合关键的安全与控制机制，ETHOS为虚拟环境中高保真、动态的人际交互奠定了实践基础。