You're reading from ROS 2 from Scratch Get started with ROS 2 and create robotics applications with Python and C++

Product type Paperback

Published in Nov 2024

Publisher Packt

ISBN-13 9781835881408

Length 380 pages

Edition 1st Edition

Concepts

Robotics

Author (1):

Edouard Renard

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Table of Contents (20) Chapters

Preface

1. Part 1:Getting Started with ROS 2

2. Chapter 1: Introduction to ROS 2 – What Is ROS 2? FREE CHAPTER

3. Chapter 2: Installing and Setting Up ROS 2

4. Chapter 3: Uncovering ROS 2 Core Concepts

5. Part 2: Developing with ROS 2 – Python and C++

6. Chapter 4: Writing and Building a ROS 2 Node

7. Chapter 5: Topics – Sending and Receiving Messages between Nodes

8. Chapter 6: Services – Client/Server Interaction between Nodes

9. Chapter 7: Actions – When Services Are Not Enough

10. Chapter 8: Parameters – Making Nodes More Dynamic

11. Chapter 9: Launch Files – Starting All Your Nodes at Once

12. Part 3: Creating and Simulating a Custom Robot with ROS 2

13. Chapter 10: Discovering TFs with RViz

14. Chapter 11: Creating a URDF for a Robot

15. Chapter 12: Publishing TFs and Packaging the URDF

16. Chapter 13: Simulating a Robot in Gazebo

17. Chapter 14: Going Further – What To Do Next

18. Index

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19. Other Books You May Enjoy

Relationship between TFs

In RViz, we have seen the links (rigid parts) and TFs (connections between the links). Links are mostly used for visual aspects in simulation and will be useful to define inertial and collision properties (when we work with Gazebo). TFs define how links are connected, and how they move between each other.

In addition to that, all the TFs for a robot are organized in a particular way, inside a tree. Let’s explore the relationship between TFs and visualize the TF tree for the robot we started on RViz.

Parent and child

Each TF will be connected to another TF, with a parent/child relationship. To see one, you can, for example, disable all TFs on RViz, and only check the base_link and gripper_pole frames.

Figure 10.5 – The relationship between two frames

As you can see in this example, an arrow is going from the gripper_pole frame to the base_link frame. This means that gripper_pole is the child of base_link ...