A white 3D printed four-legged robot standing on a desk, its body open with wiring visible

RoboticsDrawing 3 of 33

Gray
quadruped

Gray is a 12-joint quadruped robot a friend and I built in 2021 and 2022. It's in pieces on a shelf now while I teach it to walk in simulation, before any of that goes near the real robot.

StatusRobot built 2021 to 2022, software rebuilt from scratch since August 2026
Joints12 servos, three per leg, 1.96 N.m each
Mass3.1 kg
BrainRaspberry Pi, PWM at 50 Hz, three IMUs on the trunk

An open handheld controller board with two joysticks, a microcontroller and four cylindrical batteries — *PL 06*The handheld controller, built on its own board: two thumbsticks, a microcontroller and four 18650 cells.

A simulated grey quadruped robot standing on a dark checkered floor — *PL 08*The same robot in the simulator, at the ride height the walk policy starts from.

Sheet 02 of 03/Parts

Issued as separate drawings

This project is more than one project. Each part below is its own set, with its own sections and pictures.

Part 01 / 02
The machine
Twelve joints, a printed chassis and knees driven through pushrods. Designed and built with Emin Alp Arslan across 2021 and 2022, and apart on a shelf since.
2 sections →
Part 02 / 02
Learning to walk
A policy trained in simulation since August 2026: what it can do, the three things that broke getting there, and why none of it has been on the robot.
3 sections →

Sheet 03 of 03/Source

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Grayquadruped

Issued as separate drawings

The machine

Learning to walk

Inspect the work

Gray
quadruped