This work investigates how robot-mediated physicality influences the perception of social-physical interactions with virtual characters. ETHOS (Encountered-Type Haptics for On-demand Social interaction) is an encountered-type haptic display that integrates a torque-controlled manipulator and interchangeable props with a VR headset to enable three gestures: object handovers, fist bumps, and high fives. We conducted a user study to examine how ETHOS adds physicality to virtual character interactions and how this affects presence, realism, enjoyment, and connection metrics. Each participant experienced one interaction under three conditions: no physicality (NP), static physicality (SP), and dynamic physicality (DP). SP extended the purely virtual baseline (NP) by introducing tangible props for direct contact, while DP further incorporated motion and impact forces to emulate natural touch. Results show presence increased stepwise from NP to SP to DP. Realism, enjoyment, and connection also improved with added physicality, though differences between SP and DP were not significant. Comfort remained consistent across conditions, indicating no added psychological friction. These findings demonstrate the experiential value of ETHOS and motivate the integration of encountered-type haptics into socially meaningful VR experiences.

翻译：本研究探讨了机器人介导的物理性如何影响对虚拟角色社会物理交互的感知。ETHOS（按需社会交互的接触式触觉系统）是一种接触式触觉显示器，它集成了扭矩控制机械臂、可更换道具与VR头显，实现了三种手势交互：物体传递、碰拳和击掌。我们开展了一项用户研究，以检验ETHOS如何为虚拟角色交互增添物理性，及其对临场感、真实感、愉悦度和连接度指标的影响。每位参与者在三种条件下分别体验一次交互：无物理性（NP）、静态物理性（SP）和动态物理性（DP）。SP在纯虚拟基线（NP）基础上引入了可触摸道具以实现直接接触，而DP进一步融合了运动与冲击力以模拟自然触感。结果显示，临场感从NP到SP再到DP逐步提升。真实感、愉悦度和连接度也随物理性增强而改善，但SP与DP之间的差异不显著。舒适度在各条件下保持一致，表明未增加心理摩擦。这些发现证明了ETHOS的体验价值，并推动了将接触式触觉技术整合到具有社会意义的VR体验中。