Gazebo is a physics-based simulation tool used in ROS to test robots in a virtual environment before deploying them in the real world. It integrates with ROS through gazebo_ros, which acts as a communication bridge.

1. Gazebo Plugins simulate robot motion, sensors, and environment interactions.
2. Gazebo publishes joint states to ROS, which helps track the robot’s movements.
3. The robot_state_publisher node in ROS:
   • Reads the URDF (robot description).
   • Publishes TF transforms to represent the robot’s pose and link positions.
4. Other ROS tools (like RViz) can then visualize the robot’s state in real-time.

🔹 In short: Gazebo provides realistic simulation, while ROS handles data processing, control, and visualization.