Upkie Wheeled Biped

348 stars on GitHub.

Upkie is an open-source wheeled biped robot platform combining wheels for dynamic balance with articulated legs for navigating uneven terrain. Designed by Stéphane Caron and contributors, Upkie uses mjbots brushless servo actuators (mj5208 motors and qdd100 quasi-direct-drive actuators) for compliant, high-bandwidth joint control.

Source: https://github.com/upkie/upkie

The robot is built around a 3D-printed structural frame with 14 custom FreeCAD/STEP-derived printable parts covering the full body: torso case, Raspberry Pi mount, power distribution support, battery studs and shore plug, leg segments (upper leg, lower leg, hip support, knee support), wheel hubs (including an RC-variant hex hub), and optional add-ons like a handle and OAK-D Lite camera support bracket.

All structural parts are printed in PETG at 0.2mm layer height with 15-30% infill depending on load requirements. Build cost is approximately $3,000 in components with 60+ hours of printing time.

Control software runs on a Raspberry Pi and is written in Python or C++. The spine abstraction layer enables identical code to run in PyBullet/MuJoCo simulation and on the real hardware. The repo includes pre-trained balance and locomotion policies. The mjbots actuators are themselves open-source in firmware, hardware, and software.

License: Apache 2.0 (hardware parts), Apache 2.0 (software).