README.md

metadata

title: Microduck Sandbox
emoji: 🐤
colorFrom: yellow
colorTo: gray
sdk: static
pinned: false

Microduck RL playground

Real trained RL policies for the Microduck robot, running fully in the browser: MuJoCo compiled to WebAssembly steps the physics, onnxruntime-web runs the policy network at 50 Hz. No server, no backend.

Policies

Button	Checkpoint	What it does
Run	BEST_alpha_walking.onnx	Velocity-tracking locomotion (arrows / WASD to steer)
Sit	BEST_alpha_sitstand.onnx	Sits down on its hull, stands back up
Roll	roulade.onnx	Rolls over and recovers
Kick	ball_kick_left.onnx / ball_kick_right.onnx	Blind one-shot kick (0.5 s window, zeroed commands), left or right leg

Policies and MJCF model from apirrone/microduck_runtime and apirrone/mjlab_microduck.

Controls

• Arrow up / down: forward / back
• Arrow left / right: turn
• A / E: strafe
• Space: roll (one barrel roll, then back to running)
• F: kick, alternating feet
• B: pop / respawn a kickable ball in front of the duck
• C: toggle the chase camera (on by default; dragging detaches it)
• R: reset
• Drag to orbit, scroll to zoom
• Colour dots: repaint the duck (it quacks)

The ball is local-only: it lives in your tab's physics and is not shared with the multiplayer ghosts.

Gamepad

Plug in a controller and the same mapping as the real robot runtime applies:

• Left stick: forward / back + strafe
• Right stick: turn
• X: roll
• Y: pop / respawn the ball
• RB / LB: right / left kick
• D-pad down: sit / stand toggle
• Right trigger: mouth (analog) + quack

Multiplayer ghosts

Other people visiting the Space at the same time show up as translucent ducks, live. Peer-to-peer WebRTC via Trystero (serverless signaling over public Nostr relays), so it works from a static Space with no backend. Each tab broadcasts its duck's pose (trunk + 14 joints + jaw + colour) at 10 Hz; up to 3 ghosts are rendered, extra peers stay connected but invisible. The header shows "N online" when peers are around.

How it works

• rl.js fetches the MJCF (robot_allcollisions.xml), strips the visual geoms, injects a floor and a STAND keyframe, and compiles it with the official @mujoco/mujoco WASM bindings.
• The 61D observation (gyro, projected gravity, joint pos/vel, last action, command) matches mjlab_microduck/scripts/infer_policy.py.
• Rendering is a three.js rig built from kinematics.json + decimated STL meshes, driven directly from MuJoCo qpos.