HumanoidFourier (Fourier Intelligence)2025CN

Fourier N1

Name: Fourier N1
Brand: Fourier (Fourier Intelligence)

1.3 m, 38 kg humanoid launched April 2025 with open-released BOM, design drawings, assembly guides and base software.

activeBuyL2 Sim-verifiedbuildable

Difficulty index

9.9/13

9.9

Index breakdown
Class	humanoid	+5
Cost	unknown · midpoint	+1.5
DOF	23 DOF	+2.3
Parts	133 parts	+1.1

How the index works

Top of the ladder. This robot lives on the humanoid domains.

Specimen photographs

4 items

Studio render of the published MJCF, keyframe pose from the model. Geometry only; colours are the model's own materials.Rendered by Hyperspawn from mujoco_menagerie/fourier_n1 (Apache-2.0) · Hyperspawn render · source
Side view of the same MJCF render, keyframe pose from the model.Rendered by Hyperspawn from mujoco_menagerie/fourier_n1 (Apache-2.0) · Hyperspawn render · source
4 s turntable of the MJCF studio render.Rendered by Hyperspawn from mujoco_menagerie/fourier_n1 (Apache-2.0) · Hyperspawn render · source
Fourier N1 | Street Dance BotFourier · official video, embedded · source

Spec card

7/13 known

Degrees of freedom: 23
Height: 130 cm
Mass: 38 kg
Speed: 3.5 m/s
Runtime: 120 min
Part count: 133
Actuators: Fourier FSA actuators; URDF effort limits 95 N·m x4, 54 N·m x7, 30 N·m x12

Not in the registry: payload, battery, price, bom total, compute, sensors. Left blank rather than guessed.

What you learn building it

+Whole-body controlclass: humanoid
+Dozens of actuators on one busclass: humanoid
+Balance and fall handlingclass: humanoid
+Safe bring-up of a full-size machineclass: humanoid
+CNC machining: 100 partsbuild package
+12 assembly steps across 11 subassembliesbuild package
+Flashing firmware for Main computer: fourier-grx (.deb, Ubuntu 22.04 x86-64, Python 3.11; closed binary run.bin, no license), Fourier FSA actuators x23 (FSA v2 protocol over Ethernet, 48 V; actuator firmware not published), USB IMU (serial, 500 Hz)build package
+Testing in simulation (URDF/MJCF) before touching hardwareopenness
+Running published learned policiesopenness

Openness

85/100

publicCAD
publicBOM
not publicFirmware
publicSim model
publicSoftware
publicPolicies

Score 85/100 computed from what is public: CAD 25, BOM 20, sim 20, firmware 15, software 10, policies 10. Software license: MIT.

Repos & models

URDF ↗MJCF ↗MuJoCo Menagerie ↗

Site Docs

Build it

Has an ORP build package.

Build it on humanoidrobot.build ↗The hardware pack (EBOM, SolidWorks CAD, assembly guide, videos) is only on Baidu Netdisk behind a login, and carries no hardware license, so it is study-only. No part prices or purchase channel for FSA actuators.

Simulate

Load it in the browser simulator and train a policy before building.

Open on humanoidrobots.training ↗

Next rung

None. This is the top. Find people building it on humanoidrobots.team.

This is the top of the ladder.

NoteThe 23 DOF count excludes hands. The open-source package is published as the docs repo FFTAI/fourier-grx-N1 (MIT); there is no FFTAI/N1 repo. Press (Yicai, TMTPost) called it the first open-source humanoid; that claim is disputed. The MIT license covers the docs repo; no license for the hardware files was found, so hw is left undeclared. The N1 URDF (Wiki-GRx-Models, FourierN1 branch) sets a 95 N·m max effort on the four strongest joints; launch press said 96 N·m peak. Walking policies (TorchScript policy_jit_walk.pt) ship in Wiki-GRx-Deploy (FourierN1 branch) with Isaac Gym training (Wiki-GRx-Gym) and MuJoCo sim2sim (Wiki-GRx-Mujoco). fourier-grx itself is a closed binary.

Sources

[1]TMTPost: Fourier N1checked 2026-09-24
[2]Humanoids Daily N1checked 2026-09-24
[3]fourier-grx-N1 repochecked 2026-09-24
[4]N1 URDF (effort limits 95/54/30 N·m)checked 2026-09-25
[5]Wiki-GRx-Deploy FourierN1 branch (walking policies)checked 2026-09-25
[6]fourier_actuator_sdkchecked 2026-09-25
[7]Fourier N1 open-source launch pagechecked 2026-09-25
[8]N1 hardware pack on Baidu Netdisk (download needs a Baidu login)checked 2026-09-25