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DUKE HUMANOID: A BIPED THAT WALKS WITH PASSIVE DYNAMICS

A 10-joint humanoid from Duke that walks efficiently by working WITH its own physics — a measured cut in energy cost, and the code is open.

by General Robotics Lab, Duke University

FULL CAD BOM FIRMWARE DOCS

RoboticsResearch

Built withTeensy

difficulty
●●●●●
time
a serious project
license
MIT (umbrella repo only; the hardware-control and simulation submodules declare no licence)
repo
repo ACTIVE72 stars

WHAT YOU’LL NEED

Videos
1
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COMPAREE VERDICT

The Duke Humanoid is a lovely piece of engineering thinking: a 10-joint biped that walks efficiently by exploiting passive dynamics — letting the legs swing with their own physics instead of fighting them — and it posts a real, measured drop in energy cost. Duke's General Robotics Lab open-sourced the reinforcement-learning environments and the hardware control stack (Teensy firmware, EtherCAT), plus zero-shot sim-to-real walking. We're honest that this is a research platform, not a kit: there's no manufacturing CAD or BOM in the repo (the parts list lives on an external Notion page), and you'll need EtherCAT servos, a Teensy, Linux and a GPU. For a researcher or a very serious builder interested in efficient locomotion, it's a rich, credible open project.

GOOD TO KNOW

  • —The repo is an umbrella for two submodules: RL environments (legged_env) and real-hardware control (Teensy code, EtherCAT motor control). The submodules declare no licence.
  • —It has URDF and simulation STL meshes, but no manufacturing CAD (no STEP)
  • —The BOM and assembly guide live on an external Notion page, not in the repo
  • —It needs EtherCAT servos, a Teensy, Linux and an NVIDIA GPU — a research build

Parts to buy

3 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

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Can I build this?

Printsimulation meshes exist (STL), but there's no production CAD
BuyEtherCAT servos, a Teensy, compute — see the external Notion BOM
Toolselectronics bench, EtherCAT setup, a Linux + NVIDIA GPU workstation
Skillsexpert: RL, embedded control, EtherCAT
Timea serious multi-week project
Costband $$ — current prices: creator's Notion BOM
Safetya tethered biped with high-torque actuators — research-grade, no certification; keep clear of the legs when the policy is running

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

Videos

The Duke Humanoid: Design and Control For Energy Efficient Bipedal Locomotion Using Passive Dynamics2:53

The lab's paper/demo video — design and walking in one.

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Gallery

The Duke Humanoid and its cost-of-transport resultsGeneral Robotics Lab, Duke
Walking demoGeneral Robotics Lab, Duke
Second demoGeneral Robotics Lab, Duke
The robot in the demo videoGeneral Robotics Lab, Duke

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Read the project page (the overview)
  2. 2.Watch the demo (see the efficient gait)
  3. 3.Read the paper (the design and the energy results)
  4. 4.Get the BOM (Notion) (the parts list lives here)
  5. 5.Explore the code (RL env + hardware control)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • There's no manufacturing CAD or BOM in the repo — the parts list is on an external Notion page (mind link-rot)
  • It needs EtherCAT servos, a Teensy, Linux and an NVIDIA GPU — a research setup
  • It's a prototype, not a kit — treat it as a platform to study and extend

What's special about how it walks?

Its hips are symmetrical in the frontal plane, so it can stand still with straight knees, and a reinforcement-learning policy rewards it for letting the legs swing like pendulums instead of driving every joint actively — which saves energy.

How much energy does it save?

The team reports a cost-of-transport reduction of about 50% in simulation and roughly 31% on the real robot versus a baseline.

Can I build one from the repo?

Not from the repo alone — the manufacturing details and BOM are on an external Notion page, and it needs specialized servos and compute. It's a research platform.

What does it cost?

Band $$ — the EtherCAT servos and compute dominate. The Notion BOM has current prices.

Community builds

No community builds yet — be the first, we feature the best ones.

Discussion1

FROM THE COMPAREE TEAM

Duke's biped walks with straight, human-like knees and lets physics do part of the work — a measured 31 percent energy cut on real hardware. Should more humanoids stop fighting their own dynamics?

CompareeTEAM2mo ago

A gap we hit while verifying buildability: the repo has URDF and sim meshes but no manufacturing CAD at all — the actual BOM and assembly guide sit on an external Notion page, which is one link-rot away from trouble. Interesting too that the energy savings drop from about 50 percent in sim to about 31 percent on the real robot. Anyone else notice how rarely sim numbers survive contact with hardware?

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You can 3D-print your own walking Star Wars BD-X droid - fully open-source

●●●●○ · a smaller legged RL robot

Stanford Doggo: The Open-Source Robot Dog That Backflips

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General Robotics Lab, Duke University

A Duke lab open-sourced a 10-joint humanoid designed for energy-efficient walking via passive dynamics, releasing the RL environments and hardware control stack alongside the paper.

GitHub Web

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  • Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
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