Discovery Server

Note

The TurtleBot 4 should be configured for either Simple Discovery or Discovery Server, not both. See Networking for details.

Robot

  • Create® 3

    The Create® 3 needs to be updated to the latest firmware, have its Wi-Fi disabled, and be configured to use the Raspberry Pi as the discovery server over the USB-C connection.

    Setup instructions:

    • Update to the latest firmware using the webserver.
    • Once updated, perform a factory reset to disconnect the Create® 3 from any Wi-Fi networks.
    • On the webserver, go to Application -> Configuration. Save the following settings:
    Create® 3 discovery
    Create® 3 discovery server settings

    Raspberry Pi

    The Raspberry Pi needs to enable IP forwarding, configure itself as the discovery server, and reinstall the TurtleBot 4 upstart job with the new configuration. Environment variables will now be declared in /etc/turtlebot4_discovery/setup.bash, such that both the terminal and upstart environment will have the same configurations.

    Setup instructions:

    • SSH into the Raspberry Pi
    • Uncomment "net.ipv4.ip_forward=1" in /etc/sysctl.conf
    • Get and install discovery files: 
      git clone https://github.com/turtlebot/turtlebot4_setup.git -b galactic && \
sudo mv turtlebot4_setup/turtlebot4_discovery /etc/ && \
sudo mv turtlebot4_setup/scripts/install.py /usr/local/bin/ && \
rm turtlebot4_setup -rf
    • Source other workspaces in /etc/turtlebot4_discovery/setup.bash if needed
    • Add the following line to .bashrc: source /etc/turtlebot4_discovery/setup.bash
    • Re-install the upstart job with the updated install.py script:
    install.py --discovery on --workspace /etc/turtlebot4_discovery/setup.bash

    When the Create® 3 chimes, restart the robot by powering it off with the power button and placing it back on the dock.

    Tip

    You can move any ROS2 related environment variables such as ROS_DOMAIN_ID from ~/.bashrc to /etc/turtlebot4_discovery/setup.bash

  • Create® 3

    The Create® 3 needs to be updated to the latest firmware and have its Wi-Fi disabled.

    Setup instructions:

    • Update to the latest firmware using the webserver.
    • Once updated, perform a factory reset to disconnect the Create® 3 from any Wi-Fi networks.

    Raspberry Pi

    The Raspberry Pi needs to configure itself as the discovery server, and reinstall the TurtleBot 4 upstart job with the new configuration.

    Setup instructions:

    turtlebot4-setup
    • Enter the Discovery Server menu via ROS Setup.
    • Enable the discovery server.
    • Leave the IP address as 127.0.0.1, and the port as 11811.
    • Save the settings, navigate to the main menu, and apply settings.
    • Exit the setup tool
    • In your terminal, call turtlebot4-source to apply the new settings.
    • Restart the ROS 2 daemon with turtlebot4-daemon-restart or ros2 daemon stop; ros2 daemon start
    • When the Create® 3 chimes, call ros2 topic list to view topics
    Note

    When a network change occurs or a new node is added, you may need to restart the ros2 daemon to see it with ros2cli. You may also need to call ros2 topic list twice to get a full list of topics.

User PC

Because the Create® 3 is not on the same network as the user PC, an IP route has to be added to the Create® 3, through the Raspberry Pi. This route must be up at all times to maintain a connection between the PC and the Create® 3. Additionally, every device in the system must use rmw_fastrtps_cpp as their DDS and must define the ROS_DISCOVERY_SERVER environment variable to inform FastDDS of the IP and port of the server.

  • Each remote PC that will be communicating with the TurtleBot 4 will have to add an IP route for the Create® 3, as well as configure the ROS 2 environment to use the RPi4 as the discovery server. The IP route will be added using a service so that it persists through reboots.

    Get and install discovery files:

    git clone https://github.com/turtlebot/turtlebot4_setup.git -b galactic && \
sudo mv turtlebot4_setup/ip_route/ip_route.service /etc/systemd/system/ && \
sudo mv turtlebot4_setup/ip_route/ip_route.sh /usr/local/sbin/ && \
sudo mkdir /etc/turtlebot4_discovery/ && \
sudo mv turtlebot4_setup/turtlebot4_discovery/discovery_super_client.xml /etc/turtlebot4_discovery/ && \
sudo mv turtlebot4_setup/turtlebot4_discovery/setup.bash /etc/turtlebot4_discovery/ && \
rm turtlebot4_setup -rf

    Get the RPi4 Wi-Fi IP address and replace the following values with it:

    • In /usr/local/sbin/ip_route.sh, replace 10.42.0.1
    • In /etc/turtlebot4_discovery/discovery_super_client.xml, replace 127.0.0.1
    • In /etc/turtlebot4_discovery/setup.bash, replace 127.0.0.1

    Start the ip route service:

    sudo systemctl daemon-reload
sudo systemctl enable ip_route.service
sudo systemctl start ip_route.service

    Add this line to .bashrc: source /etc/turtlebot4_discovery/setup.bash

    Source .bashrc to apply settings:

    source ~/.bashrc

    Then, run:

    ros2 daemon stop; ros2 daemon start

    to restart the ROS 2 daemon.

    You should now be able to see the Raspberry Pi and Create® 3 topics:

    ros2 topic list
    Note

    When a network change occurs or a new node is added, you may need to restart the ros2 daemon to see it with ros2cli. You may also need to call ros2 topic list twice to get a full list of topics.

  • A convenient script to configure the user PC exists in the turtlebot4_setup repo.

    To download and run the script, call:

    wget -qO - https://raw.githubusercontent.com/turtlebot/turtlebot4_setup/humble/turtlebot4_discovery/configure_discovery.sh | bash <(cat) </dev/tty

    You will be prompted for a few settings:

    • The Raspberry Pi Wi-Fi IP address
    • The Discovery Server IP address (Raspberry Pi IP by default)
    • The Discovery Server port (11811 by default)
    • The ROS_DOMAIN_ID of your robot (0 by default)

    Once you have entered these values, the script will perform the following:

    • Check if an IP route already exists from a previous call of the script. If it does, delete the route.
    • Create a directory called /etc/turtlebot4_discovery/
    • Install an IP route service for the given Raspberry Pi IP address.
    • Install a FastDDS super client profile to /etc/turtlebot4_discovery/.
    • Install a setup.bash file to /etc/turtlebot4_discovery/ with the required configurations.
    • Add the line source /etc/turtlebot4_discovery/setup.bash to your ~/.bashrc file.
    • Enable and start the IP route service.

    When the script has run, call:

    source ~/.bashrc

    to apply the new settings.

    Check that the IP route has been applied by calling:

    ip route

    You should see an entry like:

    192.168.186.0/24 via 10.0.0.121 dev wlp0s20f3

    where 10.0.0.121 would be your Raspberry Pi IP, and wlp0s20f3 would be your Wi-Fi interface.

    Note

    If you cannot see the route, make sure you are able to ping your Raspberry Pi from your PC. Try manually adding the route with sudo ip route add 192.168.186.0/24 via 10.0.0.121, replacing 10.0.0.121 with yourRaspberry Pi IP.

    Then, run:

    ros2 daemon stop; ros2 daemon start

    to restart the ROS 2 daemon.

    You should now be able to see the Raspberry Pi and Create® 3 topics:

    ros2 topic list
    Note

    When a network change occurs or a new node is added, you may need to restart the ros2 daemon to see it with ros2cli. You may also need to call ros2 topic list twice to get a full list of topics.