Hardware verifiedroller skatev1.0.0Apache-2.0

Roller Skate Velocity Drive

High-speed skating locomotion utilizing passive roller skate wheels mounted under the feet, featuring asymmetric velocity limits and turn rate damping.

By Pollen Robotics @pollen-robotics

MicroDuck gliding on roller skate wheels across smooth floor

About this behavior

Converts MicroDuck into a mobile skating robot. When passive roller blade attachments are installed and D-pad up is held, robotd switches to the roller policy suite. Velocity profile allows up to +0.6 m/s forward acceleration and -0.5 m/s braking, with angular velocity clamped to 0.3 rad/s to prevent tipping.

Runtime contract

61-dimension input · 14 joint targets · 50 Hz

Show details

50 Hz / 4×slot: rollers

Observation vector61 dimensions · normalizer baked in

Proprioception48D

Positions, velocities, previous actions, gravity, and gyro.

Twist command3D

Forward, lateral, and yaw velocity intent.

Head pose4D

Neck and head orientation targets.

Body pose6D

Six-axis torso offset command.

Action targetsscale: 1×

Left leg5 joints

hip yaw · hip roll · hip pitch · knee · ankle

Neck & head4 joints

neck pitch · head pitch · yaw · roll

Right leg5 joints

hip yaw · hip roll · hip pitch · knee · ankle

Actuator model: Dynamixel XL330 (BAM M6 voltage control law). The beak motor is separate from this fixed locomotion action space.

Verification

Status: Hardware verified
Evidence: Verified on physical MicroDuck equipped with official Pollen 3D-printed roller skate foot accessories.
Target hardware: MicroDuck v1 + Roller Skate Accessories (passive bearings/wheels)
Simulation: mjlab (MuJoCo Warp) at 50 Hz
Note: Requires passive roller foot frames and 22x16x4 bearings. Robot model is robot_allcollisions_rollers.xml.

Compatibility

Robot model: microduck-rollers
MJCF model: robot_allcollisions_rollers.xml
Terrain: flat
Required accessories: roller skates

Run it on your duck

Use the canonical model and this policy slot to try the behavior locally.

slot: rollers

Try the simulation first. Hardware testing assumes a matching Microduck, clear space, and a safe surface. uDuck does not guarantee that a community policy is safe to run.

Deployment stepsShow instructions

1 Download the ONNX model BEST_roller.onnx

curl -L "https://huggingface.co/spaces/pollen-robotics/microduck-simulator/resolve/main/app/public/policies/BEST_roller.onnx" -o "/opt/robot/policies/BEST_roller.onnx"

2 Add the policy to robotd

[policy]
mode = "rollers"
roller_walk = "/opt/robot/policies/BEST_roller.onnx"

3 Restart the control loop

sudo systemctl restart robotd
robotctl health

⌁ Try it in simulation

uv run scripts/infer_policy.py --walking BEST_roller.onnx --new-cmd-obs

Sources

Upstream repositorypollen-robotics/microduck Training codeMjlab-Velocity-Flat-MicroDuck-Rollers Interactive simulatorhttps://huggingface.co/spaces/pollen-robotics/microduck-simulator