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Advanced ROS 2 Concepts

Introduction​

This document outlines advanced concepts in ROS 2 for those who have mastered the basics and wish to explore more complex functionalities. This course adopts a practical, hands-on approach to facilitate learning through direct application.

Course Origin​

The development of this course was driven by the need to provide clear and comprehensive information on intermediate and advanced ROS 2 concepts. These concepts were often challenging to find and understand, leading to the creation of a structured learning path designed to save time and reduce frustration.

Course Objectives​

The objective of this course is to provide a thorough understanding of intermediate and advanced ROS 2 functionalities. Mastery of these concepts will enhance capabilities as a ROS developer, enabling the application of this knowledge to various projects and frameworks, including ROS 2 Control, the Navigation Stack, and MoveIt.

Prerequisites​

A solid understanding of ROS 2 basics is required before starting this course. Necessary skills include:

  • Creating a package
  • Creating a node
  • Creating a subscriber
  • Working with callbacks
  • Using the command line

For those new to ROS 2, it is recommended to complete foundational courses such as "ROS 2 for Beginners, Level One" and "Level Two." However, Level Two may be skipped if the foundational knowledge is sufficient.

Course Structure​

The course is divided into four main parts, each focusing on a crucial ROS 2 concept:

  1. ROS 2 Actions
  2. Lifecycle Nodes
  3. Executors
  4. Components

Learning is facilitated through hands-on lessons, complemented by additional challenges to practice and integrate multiple concepts.

Part 1: ROS 2 Actions​

ROS 2 Actions are essential for tasks requiring feedback and the ability to be preempted. Topics covered include:

  • Structure of ROS 2 Actions
  • Creating and using action servers and clients
  • Implementing feedback and goal cancellation

Part 2: Lifecycle Nodes​

Lifecycle Nodes provide better control over node states. This part covers:

  • Node lifecycle management
  • Transition states
  • Writing lifecycle-aware nodes

Part 3: Executors​

Executors handle callbacks in ROS 2. This section explores:

  • The role of executors
  • Different types of executors
  • Customizing executors for specific use cases

Part 4: Components​

Components facilitate modular and reusable code. This part includes:

  • The concept of components in ROS 2
  • Creating and using components
  • Integrating components into projects

Hands-On Learning and Challenges​

The course emphasizes hands-on lessons to reinforce the concepts being taught. Additional challenges are provided to integrate and apply multiple concepts, aiding in the development of a comprehensive understanding of ROS 2.

Additional Resources​

These resources can provide further guidance and support throughout the learning process.