Dual_scorpion is the so-101 based integrated dual arm robot. It is the independent fork of the so-101 design repository, and is optimized for dual arm operation. We added 2 DoF to the arm created clavicle rod, spine and base.

dual_scorpion (CLI type dual_scorpion) extends the original SO-101 arm into a 7-DOF + gripper bimanual platform. The repository bundles printable parts, servo bring-up utilities, Hugging Face dataset hooks, and scripts for teleoperation, logging, and replay.

References

• Original SO-101 repository (Hugging Face LeRobot): https://github.com/huggingface/lerobot
• SO-101 hardware/software documentation on the Hugging Face Hub®: https://huggingface.co/docs/lerobot/so101
• Project overview video (YouTube): https://www.youtube.com/watch?v=a1u_bPGSeXs
• Hugging Face® is a registered trademark of Hugging Face, Inc.

Contents

• Highlights
• Quickstart
• Hardware Bring-Up
• Configuration
• Runtime Workflows
• 3D Printed Parts
• Contributing
• License

Highlights

• Dual 7-DOF follower arms with matching leader arms for real-time bimanual control.
• CLI workflows (lerobot-*) cover motor setup, calibration, teleoperation, recording, and replay.
• Hugging Face integration stores demonstrations, policies, and evaluation runs.
• dual_scorpion_3d_printer_parts/ ships STL files for both follower and leader builds.

Quickstart

Requirements

• Linux or macOS host with Python 3.10+.
• pip, venv, and a recent git.
• Feetech/BX servo buses (through the [feetech] extra).

Install

git clone https://github.com/momoiorg-repository/dual_scorpion.git
cd dual_scorpion
python -m venv .venv
source .venv/bin/activate
pip install --upgrade pip
pip install -e ".[feetech]"

Optional: authenticate with Hugging Face

huggingface-cli login
export HF_USER=<your-hf-username>

Hardware Bring-Up

1. Print & assemble the follower and leader parts from dual_scorpion_3d_printer_parts/.
2. Wire servos to their controllers, mirroring IDs between left and right buses.
3. Probe USB ports (lerobot-find-port) to map /dev/tty* or COM* devices.

Set Motor IDs

The wizard flashes IDs in this order: RIGHT gripper → joint6 … joint0, then LEFT gripper → joint6 … joint0.

• Both arms (normal)

  lerobot-setup-motors \
    --robot.type=dual_scorpion_follower \
    --robot.left_arm_port=/dev/tty.usbmodemLEFT \
    --robot.right_arm_port=/dev/tty.usbmodemRIGHT

• Left arm only (right side ignored; dummy port OK)

  lerobot-setup-motors \
    --robot.type=dual_scorpion_follower \
    --robot.left_arm_port=/dev/tty.usbmodem5A680111991 \
    --robot.right_arm_port=/dev/null \
    --arm left

• Right arm only

  lerobot-setup-motors \
    --robot.type=dual_scorpion_follower \
    --robot.right_arm_port=/dev/tty.usbmodemRIGHT \
    --robot.left_arm_port=/dev/null \
    --arm right

Notes:

• --arm accepts left, right, or both (default).
• Keep both port flags; the unused side can point to /dev/null (macOS/Linux) or NUL (Windows).
• If --arm doesn’t show up in --help, ensure you’re using the project venv binary: source .venv/bin/activate && rehash.

Calibrate Encoders

lerobot-calibrate \
  --robot.type=dual_scorpion_follower \
  --robot.left_arm_port=/dev/tty.usbmodemLEFT \
  --robot.right_arm_port=/dev/tty.usbmodemRIGHT \
  --robot.use_degrees=true

Follow the prompts to sweep every joint. Calibration artifacts are cached locally and reused by the runtime.

Configuration

All follower parameters live in src/lerobot/robots/dual_scorpion_follower/config_dual_scorpion_follower.py. Every lerobot-* CLI accepts the same keys via --robot.* flags, or you can instantiate the config directly:

from lerobot.robots.dual_scorpion_follower import DualScorpionFollowerConfig

config = DualScorpionFollowerConfig(
    right_arm_port="/dev/tty.usbmodemRIGHT",
    left_arm_port="/dev/tty.usbmodemLEFT",
    disable_torque_on_disconnect=True,
    max_relative_target=12,
    cameras={
        "top": {
            "type": "opencv",
            "index_or_path": 0,
            "width": 640,
            "height": 480,
            "fps": 30,
        },
    },
    use_degrees=True,
)

Key fields:

• right_arm_port / left_arm_port – serial device assigned to each servo daisy-chain.
• disable_torque_on_disconnect – drop torque when the driver exits (protects hardware at rest).
• max_relative_target – per-joint clamp that keeps relative commands within a safe offset (can be scalar or list).
• cameras – optional dict[str, CameraConfig] used for streaming or logging.
• use_degrees – choose between degrees and normalized joint units.

Runtime Workflows

Teleoperate

lerobot-teleoperate \
  --robot.type=dual_scorpion_follower \
  --robot.left_arm_port=/dev/tty.usbmodemFOLLOWER_L \
  --robot.right_arm_port=/dev/tty.usbmodemFOLLOWER_R \
  --teleop.type=dual_scorpion_leader \
  --teleop.left_arm_port=/dev/tty.usbmodemLEADER_L \
  --teleop.right_arm_port=/dev/tty.usbmodemLEADER_R \
  --display_data=true

The leader mirrors joint commands to the follower while streaming configured cameras.

Record Datasets

lerobot-record \
  --robot.type=dual_scorpion_follower \
  --robot.left_arm_port=/dev/tty.usbmodemFOLLOWER_L \
  --robot.right_arm_port=/dev/tty.usbmodemFOLLOWER_R \
  --teleop.type=dual_scorpion_leader \
  --teleop.left_arm_port=/dev/tty.usbmodemLEADER_L \
  --teleop.right_arm_port=/dev/tty.usbmodemLEADER_R \
  --robot.id=scorpion_follower \
  --teleop.id=scorpion_leader \
  --dataset.repo_id=${HF_USER}/dual_scorpion_demo \
  --dataset.single_task="Pick and place" \
  --dataset.num_episodes=10

Samples are written locally and pushed to the Hugging Face Hub when HF_USER is set.

Replay Policies or Datasets

lerobot-replay \
  --robot.type=dual_scorpion_follower \
  --robot.left_arm_port=/dev/tty.usbmodemFOLLOWER_L \
  --robot.right_arm_port=/dev/tty.usbmodemFOLLOWER_R \
  --dataset.repo_id=${HF_USER}/dual_scorpion_demo \
  --dataset.episode=0

For repeated evaluation runs, use scripts/replay_loop.sh after exporting HF_USER.

3D Printed Parts

dual_scorpion_3d_printer_parts/ hosts the STL sets for both follower and leader builds (base plates, spine, clavicle rods, wrists, grippers, etc.).

Acknowledgments

Dual_scorpion is designed based on the design of so-101. The development team of so-101 agreed to create a derivative model, and we are deeply grateful to them.

• Built on the SO-101 open-hardware design from the Hugging Face LeRobot project (https://github.com/huggingface/lerobot).
• Documentation and calibration guidance reference the official SO-101 guide on the Hugging Face Hub® (https://huggingface.co/docs/lerobot/so101).
• This derivative work remains under the Apache License 2.0 in alignment with the upstream project’s licensing.

Contributing

Issues and PRs are encouraged—especially around documentation gaps, new teleop tooling, and CAD improvements. Please open an issue before large hardware or API changes so we can coordinate on interfaces.

License

Apache License 2.0 (see LICENSE). Use the assets freely within the terms, and consider sharing back improvements to benefit other dual_scorpion builders.

Author: CHEN JUNGMING (陳俊銘)