Installing ROS

Table of contents

1. Getting started with ROS
2. Installing ROS
   1. Setup repositories
   2. Installation
   3. Environment setup
   4. Validating the Installation
   5. Dependencies for building packages
   6. Initialization

Getting started with ROS

The Robot Operating System (ROS) is a crucial middleware (a.k.a. collection of software packages) that enables roboticists all over the world to implement their algorithms in a clean and modular fashion and share their work effectively with the community.

In addition, it is at the very core of our class, so we’d better start playing with it!

Installing ROS

We will be using ROS 2 “Humble” in this class. If you search for ROS-related content online, you will find references to ROS 1 and ROS 2. ROS 1 has recently reached its end-of-life, and you will want to make sure you are looking at the ROS 2 version of any documentation that you find.

By now, you should have a working (preferably fresh) install of Ubuntu 22.04 and have become accustomed with the basics of Linux, Git and C++. The most efficient way to install ros is through the Debian (binary) packages.

To install ROS 2 Humble on it, we will follow the official guide to install the Desktop Install option.

Setup repositories

First we will enable the Ubuntu Universe repository

sudo apt install software-properties-common
sudo add-apt-repository universe

Next we will setup the keys (install curl if you haven’t already via sudo apt install curl)

sudo curl -sSL https://raw.githubusercontent.com/ros/rosdistro/master/ros.key -o /usr/share/keyrings/ros-archive-keyring.gpg

and then add the repository to the sources list

echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/ros-archive-keyring.gpg] http://packages.ros.org/ros2/ubuntu $(. /etc/os-release && echo $UBUNTU_CODENAME) main" | sudo tee /etc/apt/sources.list.d/ros2.list > /dev/null

Installation

Before installing ROS we need to update the apt index

sudo apt update

We also need to make sure that all packages on the system are up to date. This step may take some time.

sudo apt upgrade

Now let’s install ROS 🤖

sudo apt install ros-humble-desktop '~nros-humble-rqt*'

Environment setup

It’s convenient if the ROS environment variables are automatically loaded as soon a new shell is launched, let’s edit ~/.bashrc to do so

echo "source /opt/ros/humble/setup.bash" >> ~/.bashrc
source ~/.bashrc

By default, ROS 2 can connect to nodes on other computers on the same network. As we do not want this behavior, we will restrict ROS to only connect to nodes on the same computer:

echo "export ROS_LOCALHOST_ONLY=1" >> ~/.bashrc

Validating the Installation

We will now run some example code to make sure everything installed correctory.

In one terminal, source the setup file and then run a C++ talker:

ros2 run demo_nodes_cpp talker

In another terminal, run

ros2 run demo_nodes_py listener

You should see the talker saying that it’s Publishing messages and the listener saying I heard those messages. This verifies both the C++ and Python APIs are working properly.

Next run

printenv | grep -i ROS

and make sure ROS_DISTRO, ROS_VERSION, and ROS_PYTHON_VERSION are set:

ROS_VERSION=2
ROS_PYTHON_VERSION=3
ROS_DISTRO=humble

Dependencies for building packages

Up to now you have installed what you need to run the core ROS packages. To create and manage your own ROS workspaces, there are various tools and requirements that are distributed separately. For example, rosinstall is a frequently used command-line tool that enables you to easily download many source trees for ROS packages with one command.

To install this tool and other dependencies for building ROS packages, run:

sudo apt install python3-rosdep python3-rosinstall python3-rosinstall-generator python3-vcstool build-essential python3-colcon-common-extensions

There are several quality of life improvements related to autocomplete that you may want to add add the end of your .bashrc

eval "$(register-python-argcomplete3 ros2)"             # adds tab-completion for ros2 commands
eval "$(register-python-argcomplete3 colcon)"           # adds tab-completion for colcon commands
source /usr/share/colcon_cd/function/colcon_cd.sh       # enables colcon_cd package_name
source /usr/share/colcon_cd/function/colcon_cd-argcomplete.bash
export _colcon_cd_root=/opt/ros/humble/                 # sets the colcon_cd root

Initialization

Before using ROS, we need to initialize rosdep.

sudo rosdep init
rosdep update