Book Image

ROS Robotics By Example, Second Edition - Second Edition

By : Carol Fairchild, Lentin Joseph, Dr. Thomas L. Harman
Book Image

ROS Robotics By Example, Second Edition - Second Edition

By: Carol Fairchild, Lentin Joseph, Dr. Thomas L. Harman

Overview of this book

ROS is a robust robotics framework that works regardless of hardware architecture or hardware origin. It standardizes most layers of robotics functionality from device drivers to process control and message passing to software package management. But apart from just plain functionality, ROS is a great platform to learn about robotics itself and to simulate, as well as actually build, your first robots. This does not mean that ROS is a platform for students and other beginners; on the contrary, ROS is used all over the robotics industry to implement flying, walking and diving robots, yet implementation is always straightforward, and never dependent on the hardware itself. ROS Robotics has been the standard introduction to ROS for potential professionals and hobbyists alike since the original edition came out; the second edition adds a gradual introduction to all the goodness available with the Kinetic Kame release. By providing you with step-by-step examples including manipulator arms and flying robots, the authors introduce you to the new features. The book is intensely practical, with space given to theory only when absolutely necessary. By the end of this book, you will have hands-on experience on controlling robots with the best possible framework.
Table of Contents (18 chapters)
ROS Robotics By Example Second Edition
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Introducing rqt tools


The rqt tools (ROS Qt GUI toolkit) that are part of ROS allow graphical representations of ROS nodes, topics, messages, and other information. The ROS wiki lists many of the possible tools that are added to the rqt screen as plugins: http://wiki.ros.org/rqt/Plugins.

The ROS tutorial on the topics also describes some of the features of the rqt tool is at: http://wiki.ros.org/ROS/Tutorials/UnderstandingTopics.

rqt_graph

One of the common uses of rqt is to view the nodes and topics that are active. Bring the TurtleBot up with the minimal launch as previously described. Then, on the remote computer, issue the following command:

$ rqt_graph

Select the top-left box, Nodes/Topics (all). The following screenshot of rqt_graph shows the nodes that are active and the connections between the publishers and subscribers that deal with moving the base of the TurtleBot. Pass the cursor over the various items to see the nodes and topics and see how they communicate:

rqt_graph after minimal...