ROS2 Action Server not working in Humble

[AndrewGerstenslager]

I think there should be an additional note somewhere in the documentation if there is an incompatibility with a computer running ROS2 Humble and the Create3 in terms of action servers and possibly services (not tested). Here is the behavior as follows:

I ran the /turn_angle action on my PC running Humble. Here is the output:

andrew@andrewdesktop:~$ ros2 action send_goal /rotate_angle irobot_create_msgs/action/RotateAngle "{angle: 1.57,max_rotation_speed: 0.5}"
Waiting for an action server to become available...
Sending goal:
     angle: 1.57
max_rotation_speed: 0.5

2024-03-16 15:03:23.911 [RTPS_READER_HISTORY Error] Change payload size of '32' bytes is larger than the history payload size of '19' bytes and cannot be resized. -> Function can_change_be_added_nts

When I then installed ROS2 Galactic and ran the same command the robot worked perfectly. I'm not sure if there is a command to make Humble compatible, but I did not see any references to that. If there is an actual issue with action servers with Humble then a disclaimer would have saved me a lot of time.

[brianabouchard]

Hello! To the best of my knowledge, ROS 2 systems are not intended to be compatible across releases. If you wanted to use the Create 3 on Humble, you can install the Humble firmware on the Create 3. Here's a link to the latest versions of both Galactic and Humble: https://iroboteducation.github.io/create3_docs/releases/overview/

[shamlian]

@brianabouchard is correct. I am going to close this "not planned." Please see this ROS answer for more details: https://answers.ros.org/question/341372/can-nodes-from-different-ros-2-distributions-communicate-compatibly/ . In your case, I would recommend installing H.2.6 on your robot.

[AndrewGerstenslager]

@brianabouchard @shamlian thanks for the quick responses. My issues were less on the need to install another ROS2 version (which I had done) but moreso a suggestion to add a note about cross version compatibility on your documentation. Additionally if there is a way to figure out the version of ROS2 on the robot I'd suggest making that more clear as I couldn't find an obvious way to do that looking at the docs. Thanks for your help!

[shamlian]

The page @brianabouchard linked you to says, "Create® 3 releases take the version schema [ROS 2 letter].[major number].[minor number]. The letter corresponds with the ROS 2 Release. For example, G corresponds with Galactic, and H corresponds with Humble. See ROS 2 Releases." Similar information is also available on the Home and Update pages.

Would be happy to add information to other pages if you have suggestions, and glad you're all set.

[shamlian]

Or -- sorry -- is the suggestion to just note somewhere that the version of ROS 2 on the robot should match the version of ROS 2 on the device(s) that are communicating with it? If so, that's a reasonable suggestion. Do you think an "important" box on the "Releases" page would be a good place for that?

[AndrewGerstenslager]

Yep that's what I'm suggesting! Just something to give some clarification on the distros and how to update or check the current distro running on the bot. That way people starting their project know what version of ubuntu and ROS2 to install at the start of someone's development journey. I don't believe the documentation has a clear guideline on that from the best of my knowledge in the setup part of the documentation and think it would be a worthy addition.

[AndrewGerstenslager]

I'll look back at where I would think a good place will be. I'm busy today with a project but will be happy to offer more help tomorrow and later!