MacOS Compatibility Issues with RViz2 and the '/tf' Topic

[ygoumaz]

On macOS, RViz2 can be launched in the VM, but it encounters an error with the /tf topic.

robot_state_publisher publishes data on this topic. The data type contains a field frame_id and a field child_frame_id, which should obviously be different. On Linux and WSL, this is correct and RViz is able to use the data of the topic. On macOS, frame_id and child_fame_id are very often the same.

The only difference is the fact that Webots is started remotely, which may introduce some latency/synchronization issues.

[ygoumaz]

It can be reproduced in the macOS VM by running in the workspace:

launch_test src/webots_ros2/webots_ros2_tests/test/test_system_epuck_with_tools.py

[ygoumaz]

I also checked if it is possible to publish values to teleop_twist_keyboard topics to control the robot and it works fine on the remote instance of Webots. This means that Webots and ROS are able to communicate remotely. I doubt that the controller doesn't receive any value from Webots if it works the other way around. So it is more likely caused by the data itself or its synchronization.

[ygoumaz]

The bug is actually coming from the diff_drive_controller package, which publishes on the /tf topic.

The messages published are tfMessages containing a frame_id and a child_frame_id field in the header. These are used to build the TF tree in Rviz and they must be different. The bug comes from the fact that both fields values are set to "odom", when child_frame_id should be set to "base_link".

This bug is actually coming from the package itself and has been fixed here: ros-controls/ros2_controllers#495.

It will be available in version 2.16.0 of the package at the next sync of Humble.