Sixteen robots in OpenLoco’s UDD format as of v0.7.8, spanning seven morphology families. Every entry has a hand-authored descriptor plus pre-emitted artifacts in examples/baked/. Drop the URDF or MJCF straight into your sim — no OpenLoco binary required.
Quadrupeds with feet
Classic 12-DoF (3 per leg) wheel-less quadrupeds. Hip-roll → hip-pitch → knee-pitch chain terminating in a fixed foot.
| Descriptor | Origin | Tier | Mass | Notes |
|---|---|---|---|---|
stanford_pupper | Stanford Robotics Club | 0 | ~0.4 kg | Hobbyist BLDC; community-port |
solo12 | ODR (BSD-3) | 1 | ~2.5 kg | Research-grade brushless; community-port |
mini_pupper | Mangdang | 0 | ~0.7 kg | Mass-produced consumer kit; community-port |
mini_cheetah | MIT BRL (via chvmp/champ) | 2 | ~9 kg | Dynamic-locomotion benchmark; community-port |
spot | Boston Dynamics (public URDF) | 2* | ~32 kg | Public URDF; placeholder actuators (real Spot motors are proprietary); community-port |
Wheel-leg quadrupeds
Quadrupeds with continuous-drive wheels at each foot. Walking + driving modes.
| Descriptor | Origin | Tier | Mass | Notes |
|---|---|---|---|---|
anymal_wl | OpenLoco original | 2 | ~7 kg | ANYmal-class; both modes pass v0.5 tracking benchmarks |
anymal_wl_autonomous | OpenLoco original | 2 | ~7 kg | + RGBD + skill graph for foothold-map perception |
Air-ground hybrids
Quadrupeds whose appendages double as wheels (UGV mode) and rotors (UAS mode). Walking + flying modes.
| Descriptor | Origin | Tier | Mass | Notes |
|---|---|---|---|---|
m4_morphobot | Caltech M4 (port) | 2 | ~3.6 kg | First public CC0 implementation of the Caltech M4 morphology |
m4_morphobot_autonomous | OpenLoco original | 2 | ~3.6 kg | + VLM mode-selection skill graph |
Wheg locomotion
Three-spoke “wheg” appendages for cockroach-style emergent gaits.
| Descriptor | Origin | Tier | Mass | Notes |
|---|---|---|---|---|
mini_whegs | OpenLoco original (CWRU style) | 0 | ~0.4 kg | 3-spoke wheg crawl |
mini_whegs_autonomous | OpenLoco original | 0 | ~0.4 kg | + obstacle-height perception |
Wheeled bipeds
Two-leg morphology, each leg ending in a continuous-drive wheel. LQR-balanced (inverted-pendulum control).
| Descriptor | Origin | Tier | Mass | Notes |
|---|---|---|---|---|
upkie | upkie/upkie (Apache-2.0) | 2 | ~5 kg | First non-quadruped morphology in catalog; L/R corners, no FL/FR/RL/RR |
Manipulation arms
Single or dual serial arms terminating in a parallel gripper. Manipulation mode (no locomotion).
| Descriptor | Origin | Tier | DoF | Notes |
|---|---|---|---|---|
so100 | The Robot Studio + LeRobot | 0 | 6 | Most-installed open arm; ~$110 build; community-port |
aloha | Stanford / LeRobot (Trossen ViperX 300 ×2) | 0/1 | 14 (2×7) | Bimanual teleoperation rig; community-port |
reachy2 | Pollen Robotics | 0/1 | 18 | Humanoid upper body (head + neck + 2 × 7-DoF arms); community-port |
Aerial-only
Pure UAS, no legs, no wheels.
| Descriptor | Origin | Tier | Mass | Notes |
|---|---|---|---|---|
crazyflie | Bitcraze (BSD-3) | 0 | ~27 g | Nano quadcopter; first pure-aerial morphology in catalog; community-port |
How to use a descriptor
# Inspect the schema:
cat descriptors/anymal_wl.udd.json
# The compiler-emitted artifacts (URDF + MJCF + BOM + assembly):
ls examples/baked/anymal_wl/
The descriptor is the source of truth. Every artifact in examples/baked/<robot>/ was generated from the descriptor by the OpenLoco v0.7.8 compiler — the URDF for ROS 2 / RViz / Gazebo consumers, the MJCF for MuJoCo / MJX, the BOM for fabrication, the Markdown for assembly. No further tooling required to use these artifacts.
To modify a robot, edit its .udd.json and recompile (see how-it-works.html for the v0.7.8 → v0.7.9 source release plan).
Caveats
- Community-port descriptors carry approximate inertia tensors and joint origin offsets adapted from each project’s published URDF / CAD. They emit valid URDFs that load cleanly in ROS 2 and valid MJCFs intended for MuJoCo, but haven’t been individually verified in physics-stability tests on the v0.7.8 toolchain. The original-OpenLoco descriptors (anymal_wl, m4_morphobot, mini_whegs and their
_autonomousvariants) are verified — they pass the v0.7.8 gait + push-recovery + hover tracking benchmarks, reproducing the v0.5 Python reference numbers (and beating two of them by an order of magnitude). - Spot’s actuator dynamics are placeholder Tier 2 — the real Spot motors are proprietary and undocumented.
Want a robot that’s not in the catalog? Open an issue or send a PR with a hand-authored .udd.json. The schema is small enough that a 12-DoF quadruped is ~150 lines of JSON.