Fix ROS2 Humble RViz TF

My Gazebo hospital-auction simulation runs three TurtleBot3s under ROS 2 Humble on Ubuntu 22.04. The nodes launch without crashing, NLP commands publish correctly, yet nothing appears or moves in RViz. RViz throws its usual “Global Options → Fixed Frame does not exist” warning, so the TF tree clearly is not reaching the visualiser; after that the robots ignore the velocity messages as well. I need someone experienced with ROS 2 Humble, TF2, Gazebo / Ignition, and TurtleBot3 launch stacks to jump in, inspect the running graph, and eliminate the missing-frame problem so the three bots become visible and responsive again. I have all launch files, URDFs, and NLP command source ready to share over a screen-share or repo. You’d trace the TF broadcasts, confirm the map/odom/base_footprint chain, adjust any static transforms or frame names in the xacro + launch files, and then verify that geometry appears in RViz and that the /cmd_vel from the NLP pipeline produces motion in simulation. Deliverables – once you’re done I’d like: • A patched set of launch/URDF files or a concise diff showing the fix • A short note explaining the root cause so I can avoid it in future • Demonstration (screen recording or live session) of all three robots visible in RViz and responding to spoken commands If you’ve untangled TF “frame does not exist” errors before, this should be straightforward. Let’s get these bots moving.

Project ID: 40387238