Sending Commands from ROS 2 to RoboClaw in ROS 1 with a ROS Bridge
Introduction
With ROS 1 Noetic and ROS 2 Foxy running on the same system, it’s possible to bridge topics between them. This allows controlling a RoboClaw motor controller (running on ROS 1) using ROS 2 commands. This guide walks you through setting up the ros1_bridge and sending commands to the RoboClaw-controlled robot from ROS 2.
Key Topics Covered
- Running the RoboClaw node in ROS 1
- Setting up the ROS 1-ROS 2 bridge
- Sending velocity commands from ROS 2
- Debugging issues
1. Launching the RoboClaw Node in ROS 1
Make sure ROS 1 Noetic is sourced and start the RoboClaw node:
source /opt/ros/noetic/setup.bash
roslaunch roboclaw_node roboclaw.launch
Check if the /cmd_vel topic is available in ROS 1:
rostopic list
You should see /cmd_vel in the list.
To verify if the node is working, try publishing a command directly from ROS 1:
rostopic pub /cmd_vel geometry_msgs/Twist '{linear: {x: 0.5}, angular: {z: 0.1}}'
If the robot moves, the RoboClaw node is working correctly.
2. Setting Up the ROS 1-ROS 2 Bridge
Since ROS 1 and ROS 2 use different communication protocols, we need to bridge them.
Step 1: Install the Bridge
Ensure both ROS 1 and ROS 2 are sourced:
source /opt/ros/noetic/setup.bash
source /opt/ros/foxy/setup.bash
Install ros1_bridge:
sudo apt install ros-foxy-ros1-bridge
Step 2: Run the Bridge
ros2 run ros1_bridge dynamic_bridge
This will automatically bridge compatible topics between ROS 1 and ROS 2.
3. Sending Commands from ROS 2 to RoboClaw
Now that the bridge is running, switch to a new terminal and source ROS 2:
source /opt/ros/foxy/setup.bash
Check if the /cmd_vel topic is being bridged in ROS 2:
ros2 topic list
If /cmd_vel appears, you can publish a movement command from ROS 2:
ros2 topic pub /cmd_vel geometry_msgs/msg/Twist "{linear: {x: 0.5}, angular: {z: 0.1}}"
This should move the robot as if the command came from ROS 1.
4. Debugging Common Issues
Issue 1: ROS 1 and ROS 2 Variables Overlapping
Solution: Open separate terminals for ROS 1 and ROS 2, and source them separately.
Issue 2: The Bridge Doesn’t Forward /cmd_vel
Solution: Restart the bridge and verify that both ROS versions are sourced properly.
Issue 3: RoboClaw Doesn’t Respond to Commands
Solution: Ensure the RoboClaw node is running, and check /cmd_vel in ROS 1 using:
rostopic echo /cmd_vel
Conclusion
By following this guide, you can successfully control your RoboClaw-powered robot from ROS 2 while it runs on ROS 1 Noetic. The ros1_bridge ensures seamless communication, allowing hybrid ROS applications.
With this setup, you can integrate ROS 2-based navigation stacks with older ROS 1 hardware.