ardupilot_ros: add nav2 example on README

README.md

@@ -38,3 +38,30 @@ With the world and copter in place, launch cartographer to generate SLAM:
 ```bash
 ros2 launch ardupilot_ros cartographer.launch.py
 ```
+
+### 2. Obstacle avoidance using Cartographer and Nav2
+
+Using the same simulation as before, the nav2 node can be launched to control the copter once it is in the air.
+
+Launch the simulation:
+
+```bash
+ros2 launch ardupilot_gz_bringup iris_maze.launch.py
+```
+Launch cartographer:
+
+```bash
+ros2 launch ardupilot_ros cartographer.launch.py
+```
+
+Launch nav2:
+
+```bash
+ros2 launch ardupilot_ros navigation.launch.py
+```
+
+If you prefer, you can also run the integrated launch file:
+
+```bash
+ros2 launch ardupilot_ros obstacle_avoidance.launch.py
+```