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

Building an articulated robot arm URDF using Xacro


Our simple robot arm model rrbot consists of three link elements of various heights and two joint elements that join the links together. The joint elements each connect two of the links and enable the links to rotate around one of its axes.

In the next few sections, the rrbot URDF will be created and incrementally built to incorporate the advantages of each of the Xacro features we discussed in the last section. If you have not created the ros_robotics package, refer to the Creating and building a ROS package section in Chapter 2, Creating Your First Two-Wheeled ROS Robot (in Simulation).

Specifying a namespace

In order to create the URDF file from Xacro files, the Xacro file must contain an XML namespace declaration using the xmlns attribute with the xacro tag and corresponding URI. Here is the XML namespace (xmlns) attribute for our rrbot robot arm:

<robot name="rrbot" xmlns:xacro="http://www.ros.org/wiki/xacro">

This declaration is vital...