OpenArm#

← Tutorial Library · Other Hardware and teleoperation

This section introduces the general functions of LeRobot. Please configure the example according to the target robot, data set and operating environment; before using it with AlohaMini 2 / 2 Pro, you need to confirm the hardware and interface compatibility.

OpenArm is an open-source 7DOF humanoid arm designed for physical AI research and deployment.

To get your OpenArm, assembled or DIY, and join the global community, browse verified and certified manufacturers worldwide at openarm.dev.

What’s Unique?#

  • Human-Scale Design: OpenArm is designed with human-like proportions, scaled for a person around 160-165cm tall. This provides an optimal balance between practical reach and manageable inertia for safe, responsive operation.

  • Safety-First Architecture: Built with QDD backdrivable motors and high compliance, OpenArm prioritizes safe human-robot interaction while maintaining practical payload capabilities (6.0kg peak / 4.1kg nominal) for real-world tasks.

  • Built for Durability: Critical structural components use aluminum and stainless steel construction, ensuring robust performance for repetitive data collection and continuous research use.

  • Fully Accessible & Buildable: Every component, from CNC parts and 3D-printed casings to electrical wiring is designed to be purchasable and buildable by individual researchers and labs, with complete fabrication data provided.

  • Practical & Affordable: At $6,500 USD for a complete bimanual system, OpenArm delivers research-grade capabilities at a fraction of traditional humanoid robot costs.

Platform Requirements#

Tips

Linux Only: OpenArm currently only works on Linux. The CAN bus USB adapter does not have macOS drivers and has not been tested on Windows.

Safety Guide#

Before operating OpenArm, please read the official safety guide. Key points:

  • Secure installation: Fasten the arm to a flat, stable surface with screws or clamps

  • Safe distance: Keep body parts and objects outside the range of motion during operation

  • Protective equipment: Always wear safety goggles; use additional PPE as needed

  • Payload limits: Do not exceed specified payload limits (6.0kg peak / 4.1kg nominal per arm)

  • Emergency stop: Know the location and operation of the emergency stop device

  • Regular inspection: Check for loose screws, damaged mechanical limits, unusual noises, and wiring damage

Hardware Setup#

Follow the official OpenArm hardware documentation for:

  • Bill of materials and sourcing

  • 3D printing instructions

  • Mechanical assembly

  • Electrical wiring

The hardware repositories are available at github.com/enactic/openarm.

CAN Bus Setup#

OpenArm uses CAN bus communication with Damiao motors. Once you have the CAN bus USB adapter plugged into your Linux PC, follow the Damiao Motors and CAN Bus guide to configure the interface.

Quick setup:

# Setup CAN interfaces
lerobot-setup-can --mode=setup --interfaces=can0,can1

# Test motor communication
lerobot-setup-can --mode=test --interfaces=can0,can1

Install LeRobot 🤗#

Follow our Installation Guide, then install the Damiao motor support:

pip install -e ".[damiao]"

Usage#

Follower Arm (Robot)#

Command

lerobot-calibrate \
    --robot.type=openarm_follower \
    --robot.port=can0 \
    --robot.side=right \
    --robot.id=my_openarm_follower

API example

from lerobot.robots.openarm_follower import OpenArmFollower, OpenArmFollowerConfig

config = OpenArmFollowerConfig(
    port="can0",
    side="right",  # or "left" for left arm
    id="my_openarm_follower",
)

follower = OpenArmFollower(config)
follower.connect()

# Read current state
obs = follower.get_observation()
print(obs)

# Send action (position in degrees)
action = {
    "joint_1.pos": 0.0,
    "joint_2.pos": 0.0,
    "joint_3.pos": 0.0,
    "joint_4.pos": 45.0,
    "joint_5.pos": 0.0,
    "joint_6.pos": 0.0,
    "joint_7.pos": 0.0,
    "gripper.pos": 0.0,
}
follower.send_action(action)

follower.disconnect()

Leader Arm (Teleoperator)#

The leader arm is used for teleoperation - manually moving it to control the follower arm.

Command

lerobot-calibrate \
    --teleop.type=openarm_leader \
    --teleop.port=can1 \
    --teleop.id=my_openarm_leader

API example

from lerobot.teleoperators.openarm_leader import OpenArmLeader, OpenArmLeaderConfig

config = OpenArmLeaderConfig(
    port="can1",
    id="my_openarm_leader",
    manual_control=True,  # Disable torque for manual movement
)

leader = OpenArmLeader(config)
leader.connect()

# Read current position (as action to send to follower)
action = leader.get_action()
print(action)

leader.disconnect()

Teleoperation#

To teleoperate OpenArm with leader-follower control:

lerobot-teleoperate \
    --robot.type=openarm_follower \
    --robot.port=can0 \
    --robot.side=right \
    --robot.id=my_follower \
    --teleop.type=openarm_leader \
    --teleop.port=can1 \
    --teleop.id=my_leader

Bimanual Teleoperation#

To teleoperate a bimanual OpenArm setup with two leader and two follower arms:

lerobot-teleoperate \
    --robot.type=bi_openarm_follower \
    --robot.left_arm_config.port=can0 \
    --robot.left_arm_config.side=left \
    --robot.right_arm_config.port=can1 \
    --robot.right_arm_config.side=right \
    --robot.id=my_bimanual_follower \
    --teleop.type=bi_openarm_leader \
    --teleop.left_arm_config.port=can2 \
    --teleop.right_arm_config.port=can3 \
    --teleop.id=my_bimanual_leader

Recording Data#

To record a dataset during teleoperation:

lerobot-record \
    --robot.type=openarm_follower \
    --robot.port=can0 \
    --robot.side=right \
    --robot.id=my_follower \
    --teleop.type=openarm_leader \
    --teleop.port=can1 \
    --teleop.id=my_leader \
    --repo-id=my_hf_username/my_openarm_dataset \
    --fps=30 \
    --num-episodes=10

Configuration Options#

Follower Configuration#

Parameter

Default

Description

port

-

CAN interface (e.g., can0)

side

None

Arm side: "left", "right", or None for custom limits

use_can_fd

True

Enable CAN FD for higher data rates

can_bitrate

1000000

Nominal bitrate (1 Mbps)

can_data_bitrate

5000000

CAN FD data bitrate (5 Mbps)

max_relative_target

None

Safety limit for relative target positions

position_kp

Per-joint

Position control proportional gains

position_kd

Per-joint

Position control derivative gains

Leader Configuration#

Parameter

Default

Description

port

-

CAN interface (e.g., can1)

manual_control

True

Disable torque for manual movement

use_can_fd

True

Enable CAN FD for higher data rates

can_bitrate

1000000

Nominal bitrate (1 Mbps)

can_data_bitrate

5000000

CAN FD data bitrate (5 Mbps)

Motor Configuration#

OpenArm uses Damiao motors with the following default configuration:

Joint

Motor Type

Send ID

Recv ID

joint_1 (Shoulder pan)

DM8009

0x01

0x11

joint_2 (Shoulder lift)

DM8009

0x02

0x12

joint_3 (Shoulder rotation)

DM4340

0x03

0x13

joint_4 (Elbow flex)

DM4340

0x04

0x14

joint_5 (Wrist roll)

DM4310

0x05

0x15

joint_6 (Wrist pitch)

DM4310

0x06

0x16

joint_7 (Wrist rotation)

DM4310

0x07

0x17

gripper

DM4310

0x08

0x18

Troubleshooting#

No Response from Motors#

  1. Check power supply connections

  2. Verify CAN wiring (CAN-H, CAN-L, GND)

  3. Run diagnostics: lerobot-setup-can --mode=test --interfaces=can0

  4. See the Damiao troubleshooting guide for more details

CAN Interface Not Found#

Ensure the CAN interface is configured:

ip link show can0

Resources#