PhysicalAI Bimanual SO-101 Plugin

Third-party bimanual SO-101 robot arm plugin for PhysicalAI.

Composes two SO-101 arms (left + right) behind the Robot protocol.

Installation

uv add physicalai-bimanual-so101-plugin

feetech-servo-sdk is included as a core dependency.

Usage

Calibrated follower

import numpy as np
from physicalai.robot import connect
from physicalai_bimanual_so101_plugin import BimanualSO101

# Build left and right arms manually
from physicalai.robot.so101 import SO101, SO101Calibration

left_cal = SO101Calibration.from_path("left_calibration.json")
right_cal = SO101Calibration.from_path("right_calibration.json")

left = SO101(port="/dev/ttyACM0", calibration=left_cal, role="follower")
right = SO101(port="/dev/ttyACM1", calibration=right_cal, role="follower")

robot = BimanualSO101(left=left, right=right)

with connect(robot) as arm:
    obs = arm.get_observation()     # shape (12,)
    action = obs.joint_positions.copy()
    arm.send_action(action)

Uncalibrated bringup mode

from physicalai.robot import connect
from physicalai_bimanual_so101_plugin import BimanualSO101
from physicalai.robot.so101 import SO101

left = SO101.uncalibrated(port="/dev/ttyACM0", role="follower")
right = SO101.uncalibrated(port="/dev/ttyACM1", role="follower")

robot = BimanualSO101(left=left, right=right)

Leader (read-only teleoperation)

from physicalai.robot import connect
from physicalai.robot.so101 import SO101
from physicalai_bimanual_so101_plugin import BimanualSO101

left = SO101.uncalibrated(port="/dev/ttyACM0", role="leader")
right = SO101.uncalibrated(port="/dev/ttyACM1", role="leader")

robot = BimanualSO101(left=left, right=right)

with connect(robot) as arm:
    while True:
        obs = arm.get_observation()
        print(obs.joint_positions)

URDF Model

from physicalai_bimanual_so101_plugin import get_urdf_path

urdf_path = get_urdf_path()

Two arms mounted 0.4 m apart: left at +0.2 m (Y), right at -0.2 m (Y).

Joint Order

Left arm (indices 0-5): left_shoulder_pan, left_shoulder_lift, left_elbow_flex, left_wrist_flex, left_wrist_roll, left_gripper

Right arm (indices 6-11): right_shoulder_pan, right_shoulder_lift, right_elbow_flex, right_wrist_flex, right_wrist_roll, right_gripper

Acknowledgments

URDF model generated from Onshape via onshape-to-robot. SO-101 arm by LeRobot.