Learning ROS for Robotics Programming - Second Edition

Enrique Fernandez, Luis Sanchez Crespo, Anil Mahtani, Aaron Martinez, Luis Sanchez Crespo, Anil Mahtani

• Publisher: Packt Publishing
• Year: 2015
• ISBN:
  9781783987597
• Edition: 2
• Topic: Informatica
• Subtopic: Programmazione open source

Your one-stop guide to the Robot Operating SystemAbout This Book• Model your robot on a virtual world and learn how to simulate it• Create, visualize, and process Point Cloud information• Easy-to-follow, practical tutorials to program your own robotsIn DetailIf you have ever tried building a robot, then you know how cumbersome programming everything from scratch can be. This is where ROS comes into the picture. It is a collection of tools, libraries, and conventions that simplifies the robot building process. What's more, ROS encourages collaborative robotics software development, allowing you to connect with experts in various fields to collaborate and build upon each other's work.Packed full of examples, this book will help you understand the ROS framework to help you build your own robot applications in a simulated environment and share your knowledge with the large community supporting ROS.Starting at an introductory level, this book is a comprehensive guide to the fascinating world of robotics, covering sensor integration, modeling, simulation, computer vision, navigation algorithms, and more. You will then go on to explore concepts like topics, messages, and nodes. Next, you will learn how to make your robot see with HD cameras, or navigate obstacles with range sensors. Furthermore, thanks to the contributions of the vast ROS community, your robot will be able to navigate autonomously, and even recognize and interact with you in a matter of minutes.What's new in this updated edition? First and foremost, we are going to work with ROS Hydro this time around. You will learn how to create, visualize, and process Point Cloud information from different sensors. This edition will also show you how to control and plan motion of robotic arms with multiple joints using MoveIt! By the end of this book, you will have all the background you need to build your own robot and get started with ROS.What You Will Learn• Install a complete ROS Hydro system• Create ROS packages and metapackages, using and debugging them in real time• Build, handle, and debug ROS nodes• Design your 3D robot model and simulate it in a virtual environment within Gazebo• Give your robots the power of sight using cameras and calibrate and perform computer vision tasks with them• Generate and adapt the navigation stack to work with your robot• Integrate different sensors like Range Laser, Arduino, and Kinect with your robot• Visualize and process Point Cloud information from different sensors• Control and plan motion of robotic arms with multiple joints using MoveIt! Who This Book Is ForIf you are a robotic enthusiast who wants to learn how to build and program your own robots in an easy-to-develop, maintainable, and shareable way, this book is for you. In order to make the most of the book, you should have a C++ programming background, knowledge of GNU/Linux systems, and general skill in computer science. No previous background on ROS is required, as this book takes you from the ground up. It is also advisable to have some knowledge of version control systems, such as svn or git, which are often used by the community to share code.Style and approachThis book is an easy-to-follow guide that will help you find your way through the ROS framework. This book is packed with hands-on examples that will help you program your robot and give you complete solutions using ROS open source libraries and tools.

Learning ROS for Robotics Programming Second Edition

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Table of Contents

Learning ROS for Robotics Programming Second Edition

Credits

About the Author

Acknowledgments

About the Author

Acknowledgments

About the Author

Acknowledgments

About the Author

Acknowledgments

About the Reviewer

About the Reviewer

Acknowledgments

About the Reviewers

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Free access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Downloading the color images of this book

Errata

Piracy

Questions

1. Getting Started with ROS Hydro

PC installation

Installing ROS Hydro – using repositories

Configuring your Ubuntu repositories

Setting up your source.list file

Setting up your keys

Installing ROS

Initializing rosdep

Setting up the environment

Getting rosinstall

How to install VirtualBox and Ubuntu

Downloading VirtualBox

Creating the virtual machine

Installing ROS Hydro in BeagleBone Black (BBB)

Prerequisites

Setting up the local machine and source.list file

Setting up your keys

Installing the ROS packages

Initializing rosdep for ROS

Setting up the environment in BeagleBone Black

Getting rosinstall for BeagleBone Black

Summary

2. ROS Architecture and Concepts

Understanding the ROS Filesystem level

The workspace

Packages

Metapackages

Messages

Services

Understanding the ROS Computation Graph level

Nodes and nodelets

Topics

Services

Messages

Bags

The ROS master

Parameter Server

Understanding the ROS Community level

Tutorials to practice with ROS

Navigating by ROS Filesystem

Creating our own workspace

Creating a ROS package and metapackage

Building an ROS package

Playing with ROS nodes

Learning how to interact with topics

Learning how to use services

Using Parameter Server

Creating nodes

Building the node

Creating msg and srv files

Using the new srv and msg files

The launch file

Dynamic parameters

Summary

3. Visualization and Debug Tools

Debugging ROS nodes

Using the GDB debugger with ROS nodes

Attaching a node to GDB while launching ROS

Profiling a node with valgrind while launching ROS

Enabling core dumps for ROS nodes

Logging messages

Outputting a logging message

Setting the debug message level

Configuring the debugging level of a particular node

Giving names to messages

Conditional and filtered messages

Showing messages in the once, throttle, and other combinations

Using rqt_console and rqt_logger_level to modify the debugging level on the fly

Inspecting what is going on

Listing nodes, topics, services, and parameters

Inspecting the node's graph online with rqt_graph

Setting dynamic parameters

When something weird happens

Visualizing node diagnostics

Plotting scalar data

Creating a time series plot with rqt_plot

Image visualization

Visualizing a single image

3D visualization

Visualizing data in a 3D world using rqt_rviz

The relationship between topics and frames

Visualizing frame transformations

Saving and playing back data

What is a bag file?

Recording data in a bag file with rosbag

Playing back a bag file

Inspecting all the topics and messages in a bag file

Using the rqt_gui and rqt plugins

Summary

4. Using Sensors and Actuators with ROS

Using a joystick or a gamepad

How does joy_node send joystick movements?

Using joystick data to move a turtle in turtlesim

Using a laser rangefinder – Hokuyo URG-04lx

Understanding how the laser sends data in ROS

Accessing the laser data and modifying it

Creating a launch file

Using the Kinect sensor to view objects in 3D

How does Kinect send data from the sensors, and how do we see it?

Creating an example to use Kinect

Using servomotors – Dynamixel

How does Dynamixel send and receive commands for the movements?

Creating an example to use the servomotor

Using Arduino to add more sensors and actuators

Creating an example program to use Arduino

Using an ultrasound range sensor with Arduino

How distance sensors send messages

Creating an example to use the ultrasound range

Using the IMU – Xsens MTi

How does Xsens send data in ROS?

Creating an example to use Xsens

Using a low-cost IMU – 10 degrees of freedom

Downloading the library for the accelerometer

Programming Arduino Nano and the 10 DOF sensor

Creating an ROS node to use data from the 10 DOF sensor

Using a GPS system

How GPS sends messages

Creating an example project to use GPS

Summary

5. Computer Vision

Connecting and running the camera

FireWire IEEE1394 cameras

USB cameras

Writing your own USB camera driver with OpenCV

Using OpenCV and ROS images with cv_bridge

Publishing images with image transport

Using OpenCV in ROS

Visualizing the camera input images

Calibrating the camera

Stereo calibration

The ROS image pipeline

The image pipeline for stereo cameras

ROS packages useful for Computer Vision tasks

Using visual odometry with viso2

Camera pose calibration

Running the viso2 online demo

Running viso2 with our low-cost stereo camera

Performing visual odometry with an RGBD camera

Installing fovis

Using fovis with the Kinect RGBD camera

Computing the homography of two images

Summary

6. Point Clouds

Understanding the point cloud library

Different point cloud types

Algorithms in PCL

The PCL interface for ROS

My first PCL program

Creating point clouds

Loading and saving point clouds to the disk

Visualizing point clouds

Filtering and downsampling

Registration and matching

Partitioning point clouds

Segmentation

Summary

7. 3D Modeling and Simulation

A 3D model of our robot in ROS

Creating our first URDF file

Explaining the file format

Watching the 3D model on rviz

Loading meshes to our models

Making our robot model movable

Physical and collision properties

Xacro – a better way to write our robot models

Using constants

Using math

Using macros

Moving the robot with code

3D modeling with SketchUp

Simulation in ROS

Using our URDF 3D model in Gazebo...