Book Image

ROS Robotics By Example

Book Image

ROS Robotics By Example

Overview of this book

The visionaries who created ROS developed a framework for robotics centered on the commonality of robotic systems and exploited this commonality in ROS to expedite the development of future robotic systems. From the fundamental concepts to advanced practical experience, this book will provide you with an incremental knowledge of the ROS framework, the backbone of the robotics evolution. ROS standardizes many layers of robotics functionality from low-level device drivers to process control to message passing to software package management. This book provides step-by-step examples of mobile, armed, and flying robots, describing the ROS implementation as the basic model for other robots of these types. By controlling these robots, whether in simulation or in reality, you will use ROS to drive, move, and fly robots using ROS control.
Table of Contents (17 chapters)
ROS Robotics By Example
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Building an articulated robot arm URDF using Xacro


In the next few sections, our rrbot URDF will be created and incrementally built to incorporate the advantages of each of the Xacro features we discussed for our robot.

Using the Xacro property tag

For the first iteration of our rrbot robot arm, we will build a URDF file that defines three links with the <visual>, <collision>, and <inertial> tags, and two joints with the <parent>, <child>, <origin>, and <axis> tags. This is a very similar format to the dd_robot URDF file that you are familiar with from Chapter 2, Creating Your First Two-Wheeled ROS Robot (in Simulation). The differences for the Xacro format are listed here and explained in more detail after the code is presented:

  • Addition of the XML namespace declaration on the second line

  • Use of the Xacro <property> tag to define constant values

  • Addition of property names instead of values within the <box> and <origin> tags

  • Simple math...