Book Image

ROS Programming: Building Powerful Robots

By : Anil Mahtani, Aaron Martinez, Enrique Fernandez Perdomo, Luis Sánchez, Lentin Joseph
Book Image

ROS Programming: Building Powerful Robots

By: Anil Mahtani, Aaron Martinez, Enrique Fernandez Perdomo, Luis Sánchez, Lentin Joseph

Overview of this book

This learning path is designed to help you program and build your robots using open source ROS libraries and tools. We start with the installation and basic concepts, then continue with the more complex modules available in ROS, such as sensor and actuator integration (drivers), navigation and mapping (so you can create an autonomous mobile robot), manipulation, computer vision, perception in 3D with PCL, and more. We then discuss advanced concepts in robotics and how to program using ROS. You'll get a deep overview of the ROS framework, which will give you a clear idea of how ROS really works. During the course of the book, you will learn how to build models of complex robots, and simulate and interface the robot using the ROS MoveIt motion planning library and ROS navigation stacks. We'll go through great projects such as building a self-driving car, an autonomous mobile robot, and image recognition using deep learning and ROS. You can find beginner, intermediate, and expert ROS robotics applications inside! It includes content from the following Packt products: ? Effective Robotics Programming with ROS - Third Edition ? Mastering ROS for Robotics Programming ? ROS Robotics Projects
Table of Contents (37 chapters)
Title page
Copyright and Credits
Packt Upsell
Preface
Bibliography
Index

Inspecting the system


When our system is running, we might have several nodes and many more topics publishing messages amongst each other. We might also have nodes providing actions or services. For large systems, it is important to have tools that let us see what is running at a given time. ROS provides basic but very powerful tools with this goal in mind, from the CLI to GUI applications.

Listing nodes, topics, services, and parameters from our perspective, we should start with the most basic level of introspection. We are going to see how to obtain the list of nodes running and topics and services available at a given time:

Obtain the list of all

Command

Nodes running

rosnode list

Topics of all nodes running

rostopic list

Services of all nodes running

rosservice list

Parameters on the server

rosparam list

 

We recommend that you go back to Chapter 2, ROS Architecture and Concepts, to see how these commands also allow us to obtain the message type sent by a particular topic, as well as its fields,...