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

Baxter's arms


Baxter has seven rotary joints, as shown in the following figure. Each arm is often referred to as a 7-DOF arm, since motion of the arm is controlled by seven actuators (motors), which are capable of independent rotation.

Baxter's 7-DOF arms are described on the Rethink Robotics site at http://sdk.rethinkrobotics.com/wiki/Arms.

Baxter's arm joints

The arm joints are named in the following manner:

  • S0: Shoulder Twist (Roll)

  • S1: Shoulder Bend (Pitch)

  • E0: Elbow Twist (Roll)

  • E1: Elbow Bend (Pitch)

  • W0: Wrist Twist (Roll)

  • W1: Wrist Bend (Pitch)

  • W2: Wrist Twist (Roll)

The designation of the joints as S0, S1, E0, E1, W0, W1, and W2 enables us to define, and even monitor, each of the angles for these joints with respect to the coordinates of the joints. In ROS, the angles are measured in radians. As there are radians in a complete circle, one radian is 360/(2π), or about 57.3 degrees. A 90-degree angle is π/4, or about 0.7854 radians. These conversion values are given because it is often...