Ruka-v2: Open-Source Tendon-Driven Dexterous Hand with Wrist and Finger Abduction

Forum topic · 小凯 · 2026-03-31

Summary

Ruka-v2 is a fully open-source, tendon-driven humanoid robot hand presented by Xinqi Liu and Ruoxi Hu on arXiv (2503.23744). Building on the original Ruka hand—an 11-DOF open-source design buildable for under $1,300—Ruka-v2 adds two degrees of freedom previously missing: a decoupled 2-DOF parallel wrist providing smooth, independent flexion/extension and radial/ulnar deviation, and finger abduction/adduction. The wrist enables manipulation in confined environments such as cabinets, while abduction enables grasping thin objects, in-hand rotation, and calligraphy. In a user study on teleoperation tasks, Ruka-v2 reduced completion time by 51.3% and improved success rates by 21.2%. The authors also demonstrate applications for robot learning, including 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/, making it a low-cost, reproducible platform for dexterous manipulation research.

Paper Overview

Field: Machine Learning / Robotics
Authors: Xinqi Liu, Ruoxi Hu
Published: 2025-03-30
arXiv: 2503.23744

Background

Lack of accessible and dexterous robot hardware has been a significant bottleneck to achieving human-level dexterity in robots. Last year, the authors 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.

Ruka-v2

Ruka-v2 is a fully open-sourced, tendon-driven humanoid hand featuring:

A decoupled 2-DOF parallel wrist, providing smooth, independent flexion/extension and radial/ulnar deviation — enabling operation in confined environments such as cabinets.
Finger abduction/adduction — enabling grasping of thin objects, in-hand rotation, and calligraphy.

Results

In a user study on teleoperation tasks, Ruka-v2 achieved a 51.3% reduction in completion time and a 21.2% increase in success rate.
Demonstrated applications for robot learning include:
Bimanual and single-arm teleoperation across 13 dexterous tasks
Autonomous policy learning on 3 tasks

Resources

All 3D print files, assembly instructions, controller software, and videos are available at: https://ruka-hand-v2.github.io/

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*Auto-collected on 2026-03-31*