The growing adoption of extended reality (XR) has increased demand for wearable technologies that provide naturalistic tactile sensations while allowing users to interact freely with their environments using bare fingers. However, most existing wearable haptic devices support only a limited range of tactile modalities. Here, we introduce a soft haptic ring and a data-driven rendering methodology for generating multimodal texture sensations. The device integrates pneumatic and hydraulic actuation to render roughness, thermal, and softness cues on the proximal phalanx. The ring can generate forces up to 1.75 N, produce displacements up to 0.27 mm within a 30-300 Hz operating range, and modulate display temperature by up to 25 Celcius within 65 s. The rendering methodology modulates these cues based on the user's exploratory actions: the hydraulic actuator conveys perceived temperature during static contact, while the pneumatic actuator generates pressure and vibration cues to convey softness and roughness during pressing and sliding gestures, respectively. We evaluated the system in a user study with 15 participants who matched six virtual textures generated by the ring to their real counterparts and rated their perceived sensations using guided exploratory actions. Participants achieved an average texture-matching precision of 68% and an F1 score of 0.68. Adjective ratings confirmed that the ring produces distinct and perceptually rich stimuli across all rendered modalities. These findings demonstrate the potential of the proposed haptic ring and rendering methodology to deliver multimodal tactile cues away from the fingertip for immersive XR applications, enabling diverse tactile feedback while preserving natural physical interaction.

翻译：扩展现实（XR）技术的日益普及，推动了对可穿戴技术产品的需求增长，这些产品需在提供逼真触觉感受的同时，允许用户使用裸手与周围环境自由交互。然而，现有大多数可穿戴触觉设备仅支持有限的触觉模态。本文介绍了一款软体触觉环及一种数据驱动的渲染方法，用于生成多模态纹理感知。该设备集成了气动与液压驱动机制，可在近端指骨区域呈现粗糙度、热觉与柔软度提示。该环可产生高达1.75 N的力，在30-300 Hz工作范围内实现高达0.27 mm的位移，并在65秒内调节显示温度高达25摄氏度。所提出的渲染方法根据用户的探索动作调制上述提示：静态接触时，液压执行器传递感知温度；按压与滑动手势中，气动执行器分别生成压力与振动提示以传递柔软度与粗糙度感知。我们开展了一项包含15名参与者的用户研究来评估系统性能，参与者需将环生成的六种虚拟纹理与其真实对应物进行匹配，并依据引导性探索动作对感知体验进行评分。参与者平均纹理匹配精度达68%，F1分数为0.68。形容词评分证实，该环在所有渲染模态下均能产生清晰且感知丰富的刺激。这些发现表明，所提出的触觉环及渲染方法具有在指尖以外区域传递多模态触觉提示的潜力，可用于沉浸式XR应用，在保留自然物理交互的同时提供多样化触觉反馈。