ROS 2 Robotics Development

This skill covers building ROS 2 packages and nodes, including package structure, communication patterns (topics, services, actions), timing and frames, build/test workflows with colcon, and common pitfalls in robotics software.

Workflow for Building a ROS 2 Package

1. Scaffold the package — Run ros2 pkg create --build-type ament_python <name> (Python) or --build-type ament_cmake <name> (C++) inside a colcon workspace's src/ directory.
2. Define interfaces — Add custom .msg, .srv, or .action files under msg/, srv/, action/ only when a standard interface (std_msgs, geometry_msgs, sensor_msgs, nav_msgs) doesn't fit.
3. Implement nodes — Write focused, composable nodes; declare parameters explicitly; choose topics for streams, services for quick request/response, and actions for long-running goals with feedback and cancellation.
4. Write launch files — Compose nodes, parameters, and remappings in a launch/*.launch.py file using launch_ros.actions.Node.
5. Set QoS profiles intentionally — Match publisher/subscriber QoS (reliability, durability, history depth) for sensor data vs. command/control paths.
6. Build the workspace — Run colcon build --symlink-install from the workspace root, then source install/setup.bash.
7. Test — Add unit tests (pytest for Python, gtest/launch_testing for C++/integration) and run colcon test.
8. Run and inspect — Use ros2 run, ros2 launch, ros2 topic echo, ros2 node info, and ros2 doctor to verify runtime behavior.

Package Structure