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：缺乏可获取的灵巧机器人硬件一直是实现类人灵巧操作的重大瓶颈。去年，我们发布了Ruka——一款完全开源的腱驱动机器人手，具备11个自由度（每指2个，拇指3个），制造成本低于1300美元。作为首批完全开源的人形手之一，它引入了一种新型数据驱动的手指控制方法，在控制系统中捕捉腱动力学特性。尽管有这些贡献，Ruka仍缺少两个对精确模仿人类行为至关重要的自由度：手腕活动性与手指外展/内收。本文提出Ruka-v2：一款完全开源的腱驱动人形手，采用解耦的双自由度并联手腕和手指外展/内收结构。并联手腕可独立实现平滑的屈伸与桡尺偏运动，从而支持在橱柜等受限环境中的灵巧操作；手指外展功能则实现了薄物抓取、掌内旋转及书法书写等动作。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对比评估，发现任务完成时间缩短51.3%，成功率提升21.2%。我们进一步展示了其在机器人学习中的完整应用：覆盖13项灵巧任务的双手与单臂遥操作，以及3项任务的自主策略学习。所有3D打印文件、装配指南、控制器软件及演示视频均发布于 https://ruka-hand-v2.github.io/ 。