Lack of accessible and dexterous robot hardware has been a significant bottleneck to achieving human-level dexterity in robots. Last year, we released Ruka, a fully open-sourced, tendon-driven humanoid hand with 11 degrees of freedom - 2 per finger and 3 at the thumb - buildable for under $1,300. It was one of the first fully open-sourced humanoid hands, and introduced a novel data-driven approach to finger control that captures tendon dynamics within the control system. Despite these contributions, Ruka lacked two degrees of freedom essential for closely imitating human behavior: wrist mobility and finger adduction/abduction. In this paper, we introduce Ruka-v2: a fully open-sourced, tendon-driven humanoid hand featuring a decoupled 2-DOF parallel wrist and abduction/adduction at the fingers. The parallel wrist adds smooth, independent flexion/extension and radial/ulnar deviation, enabling manipulation in confined environments such as cabinets. Abduction enables motions such as grasping thin objects, in-hand rotation, and calligraphy. We present the design of Ruka-v2 and evaluate it against Ruka through user studies on teleoperated tasks, finding a 51.3% reduction in completion time and a 21.2% increase in success rate. We further demonstrate its full range of applications for robot learning: bimanual and single-arm teleoperation across 13 dexterous tasks, and autonomous policy learning on 3 tasks. All 3D print files, assembly instructions, controller software, and videos are available at https://ruka-hand-v2.github.io/ .

翻译：缺乏可获取且灵巧的机器人硬件，一直是实现机器人人类级灵巧操作的主要瓶颈。去年，我们发布了Ruka——一款完全开源、基于腱驱动的人形手，拥有11个自由度（每指2个、拇指3个），制造成本低于1300美元。这是首批完全开源的人形手之一，并引入了一种新颖的数据驱动手指控制方法，可在控制系统中捕获腱动力学特性。尽管有这些贡献，Ruka仍缺失两个对精确模仿人类行为至关重要的自由度：腕关节活动性与手指内收/外展功能。本文提出Ruka-v2：一款完全开源、基于腱驱动的全人形手，其特点是配备解耦的双自由度并联腕关节，以及手指的内收/外展功能。并联腕关节可实现平滑且独立的屈伸运动与桡尺偏运动，从而能在橱柜等受限环境中进行操作；外展功能则支持抓取薄物体、手内旋转及书法等动作。我们介绍了Ruka-v2的设计，并通过遥操作任务的用户研究将其与Ruka进行对比评估：任务完成时间减少51.3%，成功率提升21.2%。进一步展示了其在机器人学习中的全方位应用：涵盖13项灵巧任务的双手及单臂遥操作，以及3项任务的自主策略学习。所有3D打印文件、装配说明、控制器软件及视频均见https://ruka-hand-v2.github.io/。