Issue with /diff_drive/scan and /diff_drive/odometry Topics Returning Zero or Infinity Values

[DWDROME]

Hi,

I am encountering an issue with my setup where the values published on the /diff_drive/scan and /diff_drive/odometry topics are either 0 or infinity (inf). This occurs when I try to echo these topics using the following commands:

ros2 topic echo /diff_drive/scan
ros2 topic echo /diff_drive/odometry

The expected output should be valid sensor data and odometry information, but instead, I receive values of 0 or inf, which seems incorrect.

Environment:

• ROS 2 Jazzy
• Gazebo Harmonic
• ros_gz_project_template setup for SLAM and robot simulation

Troubleshooting:

• I have tried using both gz topic and ros2 topic to check the /diff_drive/scan and /diff_drive/odometry topics, and both methods return 0 or inf.
• I suspect this issue may be related to time synchronization, but I am unsure if that's the cause.
• I have also checked that the remappings are correct in the Cartographer configuration file, but the issue persists.

Steps to Reproduce:

1. Launch the simulation with Gazebo and Cartographer.
2. Run the following command to echo the topics:

   ros2 topic echo /diff_drive/scan
   ros2 topic echo /diff_drive/odometry

3. Observe the output showing only 0 or inf.

Any suggestions or guidance would be greatly appreciated!

Thank you for your time and support.

Best regards,
陈梓洋

[DWDROME]

sorry,here is the Correction
Issue Details:
Gazebo (gz): The /diff_drive/scan and /diff_drive/odometry topics in Gazebo return the expected values (valid sensor data and odometry).
ROS 2 (ros2 topic echo): In ROS 2, when I try to echo the same topics, I get values of 0 or inf, which seems incorrect.
Troubleshooting:
I've checked that the remappings in the Cartographer configuration are correct, but the issue persists in ROS 2.
I suspect it could be an issue related to time synchronization between Gazebo and ROS 2, but I am unsure if that's the root cause.