u/Glittering-Leading92

After 8–10 days of struggles and debugging, I finally managed to build a closed-loop vision-based line follower robot using ROS2, URDF, and Gazebo.

The hardest part for me wasn’t designing the robot or making it move, but actually using the camera sensor to detect the track and make the robot follow it. Initially I thought I would need to deeply learn OpenCV, but for this project I ended up needing only a handful of functions, which I learned along the way.

I also reused some ideas from my first ROS2 project (a turtle follower), especially integrating PID control for smoother turning behavior. The bot still struggles a bit with sharp 90° turns, probably due to PID tuning or camera resolution/FOV limitations, but overall the tracking is fairly stable.

The project uses:

• ROS2
• Gazebo
• URDF
• OpenCV + cv_bridge
• PID control
• Camera-based centroid tracking using image moments

(i used chatgpt to organise the uses into points)
(will add github link later-on)

for a recent project, i wanted a black track so i downloaded one from the gazebosim website but it didn't have a .dae file. I sourced the track's .sdf file into my project and made it default so that my robot would spawn in the track's world instead of my own world. Another problem came which was that my robot model was falling down endlessly because the track's file didn't have <collision> tags, so added a ground having diffuse/ambient (done by Claude), managed to turn the track black by adjusting things, but now the ground looks shadowy as yall can see. How to make the ground look normal ? I can add my world's code if needed

Edit: I found out my mistake when i was trying to use camera plugin in the file. <model> and <world> are two different things, and i couldn't use world-level features like Sensors plugin, which made me change the whole file.