BuildROS2

⚠️ ROS 2 broadcasts (a lot)

By default, ROS2 broadcasts messages based on your network mask settings. If you have multiple computers on the same subnet/mask, they will all share the same "space" by default. So if you start 2 instances of the dVRK console they will use the same topics, services, tf names... This is a bit dangerous as you might be controlling someone else's robot by accident. There are multiple ways to handle this but here are two simple solutions that should cover most cases:

All your ROS node will be on the same computer and nobody else has nodes running on the same computer, use the local host only approach
Your nodes might be spread on multiple computers or there's a chance another user has ROS nodes on any of the computers you're using, domain ID will work (as long as no one uses the same ID)
⚠️ If you use any of the methods below and need to test the results, make sure you stop and restart the ROS 2 daemon after your export/unset since it will cache some of the discovery information: ros2 daemon stop; ros2 daemon start

Local host

You can set a unique ROS Domain ID , either in your own ~/.profile or for all users with /etc/profile.d/ros2.sh.

export ROS_LOCALHOST_ONLY=1

Note that the variable ROS_LOCALHOST_ONLY just has to be defined. Setting it to 0 doesn't turn this feature off, you would have to use unset to disable the local host only broadcast.

Domain ID

You can set a unique ROS Domain ID , either in your own ~/.profile or for all users with /etc/profile.d/ros2.sh.

export ROS_DOMAIN_ID=33

If your organization uses a centralized authentication server (SSO), one can use the Unix user ID to define the ROS Domain ID. Unfortunately the domain ID should be between 0 and 101 (see ROS_DOMAIN_ID) so we can't use the full Unix user Id To automatically set the ROS Domain ID. The following configuration file will generate the domain ID based on the last 2 digits of the user ID. Create or edit the file /etc/profile.d/ros2.sh to contain:

# set domain id based on last 2 digits of user id
export ROS_DOMAIN_ID=$(id -u | rev | cut -c 1-2 | rev)

⚠️ Since this relies on the last two digits of the user ID, there is still a strong possibility 2 users will have the same ROS Domain ID. Make sure you run ros2 node list to check nobody is using your domain.

Usage

Example of session

Terminal 1: starting the dVRK main console

with a real system:

source ~/ros2_ws/install/setup.bash
cd ~/ros2_ws/install/dvrk_config_jhu # we assume each group has created their own configuration file repository!
ros2 run dvrk_robot dvrk_console_json -j share/jhu-dVRK-Si/console-PSM1.json

with a simulated arm:

source ~/ros2_ws/install/setup.bash
cd ~/ros2_ws/install/sawIntuitiveResearchKitAll/share/sawIntuitiveResearchKit
ros2 run dvrk_robot dvrk_console_json -j share/console/console-PSM1_KIN_SIMULATED.json

Terminal 2: using a Python test script to make the arm move

source ~/ros2_ws/install/setup.bash
ros2 run dvrk_python dvrk_arm_test.py -a PSM1

Terminal 3: starting the ROS 2 joint and robot state publishers so we can visualize the arm in RViz

source ~/ros2_ws/install/setup.bash
ros2 launch dvrk_model dvrk_state_publisher.launch.py arm:=PSM1

Terminal 4: starting RViz

source ~/ros2_ws/install/setup.bash
ros2 run rviz2 rviz2 -d ~/ros2_ws/install/dvrk_model/share/dvrk_model/rviz/PSM1.rviz

Note that all the configuration files are installed in the ros2_ws/install directory during the build so you can automatically locate them when you write your own ROS launch files.