Welcome to A Guide to ROS2 — A Guide to ROS2

Overview

Robot Operating System 2 (ROS2), is a modern middleware framework for robotics development. It is designed to support real-time control, distributed systems, and scalable multi-robot applications.

This module uses ROS 2 as the foundation because:

• It is actively maintained and continuously improved by the open-source robotics community.
  • As of May 31, 2025, the ROS 1 Noetic distribution has officially reached its end-of-life (EOL). This means it will no longer receive bug fixes, security updates, or official support.
• It supports real-time capabilities, secure communication, and managed node lifecycles — features that are critical for today’s complex robotic systems.
• It works across multiple platforms, including Linux, Windows, and macOS.

In this module, I’ll give you a simplified introduction to key ROS 2 concepts to help you get started. For more detailed information, refer to the linked guide at the top of this page.

Basic ROS2 Concepts

ROS 2 is built on a modular architecture. This means it breaks a robot’s software system into separate, manageable parts that each handle a specific task.

Some of the core building blocks in ROS 2 include:

• Nodes: Independent processes that perform specific computations
• Topics: Communication channels for sending data between nodes. Asynchronous
• Services: Request/response interactions. Synchronous communication
• Actions: Long-running tasks, offer feedback and goal tracking
• Parameters, Launch files, and Packages

Nodes and Topics

In ROS 2, nodes are the basic execution units. Each node should be responsible for a singular, modular purpose — such as sensing, processing data, or controlling motors. Nodes are designed to run independently, making it easy to develop and debug different parts of a robot separately.

The communication between nodes are enabled by messages. A message is a structured data format that contains specific fields for data values. It can contain a simple value (like temperature) or complex structures (like a robot's position in space). The structure of a message is defined in its .msg file.

To transmit messages, ROS 2 uses topics. When a node wants to send data, it publishes a message to a topic. Other nodes that need this data will subscribe to the same topic to receive those messages. This model is asynchronous and allows for flexible, real-time communication between multiple nodes.