RUKA: Rethinking the Design of Humanoid Hands with Learning

New York University
RSS 2025

Abstract

Dexterous manipulation is a fundamental capability for robotic systems, yet progress has been limited by hardware trade-offs between precision, compactness, strength, and afford- ability. Existing control methods impose compromises on hand designs and applications. However, learning-based approaches present opportunities to rethink these trade-offs, particularly to address challenges with tendon-driven actuation and low-cost materials.

This work presents RUKA, a tendon-driven humanoid hand that is compact, affordable, and capable. Made from 3D-printed parts and off-the-shelf components, RUKA has 5 fingers with 15 underactuated degrees of freedom enabling diverse human-like grasps. Its tendon-driven actuation allows powerful grasping in a compact, human-sized form factor. To address control challenges, we learn joint-to-actuator and fingertip-to- actuator models from motion-capture data collected by the MANUS glove, leveraging the hand's morphological accuracy. Extensive evaluations demonstrate RUKA's superior reachability, durability, and strength compared to other robotic hands. Tele- operation tasks further showcase RUKA's dexterous movements. The open-source design and assembly instructions of RUKA, code, and data are available on our website.

Hardware

The Ruka hand costs less than $1300 and can be assembled in under 7 hours with common hand tools.
Finger Dowel Assembly GIF
Finger Springs and Screws Assembly GIF
For the instructions on hardware assembly, please visit ruka.gitbook.io/instructions.

Teleoperation

MANUS MoCap Glove teleoperation

Screwdriver (2x)

Music Box (2x)

Eraser Flipping (2x)

Battery (2x)

Saw (20x)

Nutella (5x)

VR Headset for teleoperation with OpenTeach

Water Bottle

Controller Learning

RUKA uses data and learning to address control. It learns per-finger controllers that map fingertip positions to motor commands using data collected with motion-capture gloves.
Data Collection

Durability And Strength Test

RUKA can run for 20 hours without overheating.
RUKA outperforms other hands in strength tests.
Strength Test Demonstration Strength Test Demonstration

Policy Learning - HuDOR

We used RUKA to train autonomous policies using HuDOR. Learned residual motor policies converged in 45 mins over 40 episodes.

Before HuDOR

After HuDOR

Grasp Test

Grasp Test Demonstration

Acknowledgements

We thank Raunaq Bhirangi, Siddhant Haldar and Venkatesh Pattabiraman for valuable feedback and discussions. This work was supported by grants from Honda, Hyundai, NSF award 2339096, and ONR award N00014-22-1-2773. LP is supported by the Sloan and Packard Fellowships. NXB is supported by the Fannie and John Hertz Foundation Fellowship.

BibTeX

@article{zorin2025ruka,
  title={RUKA: Rethinking the Design of Humanoid Hands with Learning},
  author={Zorin, Anya and Guzey, Irmak and Yan, Billy and Iyer, Aadhithya and Kondrich, Lisa and Bhattasali, Nikhil X. and Pinto, Lerrel},
  journal={Robotics: Science and Systems (RSS)},
  year={2025}
}