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I've added sensors to the mobile platform of my robot. However, I cannot visualize the sensor information and get the following messages when running the simulation.

[robot_state_publisher-4] [WARN] [1715735323.806351232] [robot_state_publisher]: Moved backwards in time, re-publishing joint transforms!

When I add the sensor for visualization in RVIZ, this message appears:

[rviz2-6] [INFO] [1715738559.972740221] [rviz2]: Message Filter dropping message: frame 'camera_link_optical' at time 13366.683 for reason 'the timestamp on the message is earlier than all the data in the transform cache'

Any ideas as to what could be causing the problem? And does the parent link of the sensor need to be a fixed link?

The TF2 frames look like this

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  • $\begingroup$ neither of those are labeled as errors... the first one is a warning ... the second one is info $\endgroup$
    – jsotola
    Commented May 15 at 2:38

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1- Check your Urdf on Urdf folder

check_urdf name_of_robot_urdf.urdf

2-Then check the TF frames if they are properly transformed

ros2 run tf2_tools view_frames

Open and examine the generated frames.pdf file

evince frames.pdf

3-Usually camera requires camera_info parameters to be set to get the image on rviz2.

4-QoS reliability can also raise issues. Try change from Reliable to Best Effort on rviz2 or the inverse...Are you using some package for camera or just getting images? Packages can be compatible to a specific type of QoS.

5-You can also check the transform of frames from sensor_link to your parent link to check if they are ok:

ros2 topic echo /tf2_echo frame_parent camera_link_optical 

replace the frame_parent by the parent frame of your camera sensor.

6- Are you launching the robot_state_publisher and joint_state_publisher with no errors?

7 using sim_time=true in all configuration files and nodes launched is a good idea.

The parent_link does not need to be fixed, but the transforms must be working properly (joint state, robot state publishers). I mean if you review the logs on terminal output more carefully it can brings more valuable and specific information and then examine what can be missing or wrong in launch file or configurations file.

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