Dual-Arm NERO CAN Teleoperation Tutorial

Dual-arm robots are becoming increasingly important in embodied AI, teleoperation, imitation learning, and collaborative manipulation research.

This tutorial demonstrates how to configure two AgileX NERO 7-DOF robotic arms in a leader-follower setup using CAN bus communication. Once configured, the follower arm will automatically replicate the motion of the leader arm in real time.

What You'll Build

By the end of this guide, you'll be able to:

✅ Synchronize two NERO robot arms

✅ Enable real-time leader-follower motion following

✅ Configure CAN-based dual-arm communication

✅ Validate coordinated dual-arm operation

✅ Prepare a platform for teleoperation and imitation learning experiments

Hardware Requirements

Step 1: Connect the CAN Bus

The first step is connecting the CAN communication lines between the two robot arms.

Wiring Rules

Connect:

• CAN H ↔ CAN H
• CAN L ↔ CAN L

Important

Before powering on:

• Verify all connectors are secure.
• Ensure there are no loose contacts.
• Check that CAN H and CAN L are not reversed.

Incorrect wiring may prevent communication between the two robotic arms.

Step 2: Configure Leader and Follower Modes

Once the CAN bus connection is complete, assign the role of each robot arm.

Leader Arm

The leader arm acts as the command source.

Responsibilities:

• Generates motion commands
• Broadcasts joint states
• Controls overall synchronization

Follower Arm

The follower arm executes the motion commanded by the leader arm.

Responsibilities:

• Receives leader motion data
• Replicates joint trajectories
• Mirrors the leader's pose in real time

After configuration, save all parameters before proceeding.

Safety Warning Before Activation

⚠️ Read This Before Enabling Leader-Follower Mode

Before assigning leader-follower roles:

1. Move both robotic arms close to their home positions.

2. Ensure the workspace is clear.

3. Remove any obstacles around the robot.

When synchronization is activated, the follower arm immediately attempts to match the leader's current pose.

If the initial poses differ significantly, the follower arm may move rapidly, potentially causing:

• Robot collisions
• Pinch hazards
• Hardware damage
• Personal injury

For safe operation, always align both robots before enabling synchronization.

Step 3: Validate Leader-Follower Synchronization

After configuration, verify that communication and synchronization are functioning correctly.

Validation Procedure

1. Check CAN Connections

Verify:

• CAN H is connected correctly
• CAN L is connected correctly
• No loose cables exist

2. Verify Control Modes

Confirm:

• Leader mode is enabled
• Follower mode is enabled
• Parameters have been saved successfully

3. Move the Leader Arm

Manually operate the leader arm.

4. Observe the Follower Arm

The Follower arm should:

• Follow every joint movement
• Replicate end-effector trajectories
• Maintain smooth synchronized motion

Successful tracking indicates that Leader-Follower control is operating correctly.

Software Version Notes

Version 1.1 API Limitation

For NERO software version 1.1:

When Leader-Follower mode is enabled:

• API access is limited to commands issued by the leader arm.
• Independent follower-arm state information cannot be queried separately.

Developers building custom applications should account for this behavior when logging data or implementing monitoring systems.

Conclusion

Using a simple CAN bus connection, two NERO 7-DOF robotic arms can be configured into a synchronized leader-follower system capable of real-time trajectory replication and coordinated motion control.

This setup is particularly useful for:

• Embodied AI development
• Teleoperation platforms
• Imitation learning pipelines
• Robot data collection
• Research and education

By following the wiring, configuration, and safety recommendations in this guide, developers can quickly deploy a reliable dual-arm robotic platform for experimentation and application development.

FAQ

Q1：Why does the follower arm move suddenly when leader-follower mode is enabled?

When leader-follower mode is activated, the follower arm immediately attempts to match the current pose of the leader arm.

If the two arms start from significantly different positions, the follower arm may perform a rapid corrective movement.

Q2：The follower arm is not following the leader arm. What should I check first?

Verify the following items:

• CAN H and CAN L are connected correctly.
• Leader and follower modes are configured properly.
• Configuration settings have been saved.
• The CAN cable is firmly connected.
• Both robot arms are running compatible software versions.

In most cases, incorrect CAN wiring or unsaved configuration parameters are the root causes.

Q3：Why does the follower arm stop responding after working correctly for a period of time?

This behavior is typically caused by:

• Loose CAN connectors
• Unstable power supply
• CAN bus communication interruptions
• Software configuration changes

Check cable integrity, power stability, and communication status before restarting the system.

Q4：What should I do if the follower arm's motion does not exactly match the leader arm?

Check the following:

• Joint calibration status
• Home position accuracy
• Mechanical interference
• Firmware version consistency
• CAN communication quality

Small tracking errors can often be reduced by recalibrating both robot arms and ensuring they start from similar initial poses.

💬 Have Question?

If you encounter any issues with environment installation, parameter configuration, or RL training, feel free to leave your questions for further discussion.