Open Duck Mini

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Open Duck Mini — Bipedal BDX Droid Replica

Source: https://github.com/apirrone/Open_Duck_Mini

A miniature bipedal character robot inspired by Disney's BDX droid (the little star of the Galactic Starcruiser walkabout experience and several Disney+ trailers). Designed by Antoine Pirrone (apirrone), Open Duck Mini scales that silhouette down to about 35 cm tall and lets you build one for a few hundred dollars in parts.

What it is

A walking, head-tilting, antenna-twitching little biped with serious character. Under the cute exterior it's a legitimate RL-trained biped:

• Legs trained in Isaac Gym, sim-to-real transferred to physical hardware
• Standing-up-from-fall policy with demonstrated perturbation robustness
• Sim2Sim pipeline through Mujoco for validation before hardware deployment
• Head + antennas add expressiveness on top of the locomotion stack

Hardware

• Servos: Dynamixel XC330-M288-T across all joints (upgraded from XL330 for torque headroom on landing impacts)
• IMU: BNO055 9-axis for base orientation estimate
• Compute: an onboard board (RPi-class or similar SBC) running the learned policy
• Battery: small LiPo in the cage, hot-swappable

What you can do with it

• Run the pretrained walking policy straight from the repo — step the robot around, send it forward/turn commands over the orobot cloud surface.
• Collect your own episodes — use the remote surface here as the operator input for demos.
• Research biped RL — swap in your own PPO / SAC training runs; the Mujoco and Isaac scenes are all published.
• Character animation — antenna and head servos give it genuine personality for demos, events, or as a companion prop.

Printed parts (canonical set shipped with this program)

• head, body_part — shell and torso
• hip_left_roll_to_pitch, hip_right_roll_to_pitch — hip assemblies
• renfort_leg — leg reinforcement
• axis_to_axis, block_to_axis — joint linkages
• foot — contact surface
• cage_top, cage_bottom, cage_back — internal electronics cage
• antenna, antenna_tip — head antennas

The full repo includes ~130 STLs covering wiring routing, battery variants, and community mods (see Jaime's v2 mods and Justin's "Park Head" variant in the upstream print/mods/ tree).

Attribution & license

• Designer: Antoine Pirrone (apirrone)
• Upstream: https://github.com/apirrone/Open_Duck_Mini
• License: Apache 2.0
• Related: Duck community mods + variants under print/mods/ in the upstream repo

Links

• Upstream: https://github.com/apirrone/Open_Duck_Mini
• Training code: https://github.com/apirrone/Open_Duck_Mini_Runtime
• BDX inspiration: Disney's Galactic Starcruiser droid

Install Notes

The orobot start action runs the MuJoCo simulation training script (v2_rl_walk_mujoco.py), not the physical robot deployment. The actual walking firmware for the physical duck lives in a separate repository: apirrone/Open_Duck_Mini_Runtime. To run on hardware, clone the Runtime repo separately, deploy to a Raspberry Pi Zero 2W, and update the start action in this Program's editor to point at the Runtime's main script.