How to Create a ROS 2 Package – Iron

giant-robotic-arm-in-a-factory

In this tutorial, we will go over how to create a ROS 2 package.

A ROS 2 package is the fundamental building block of robot software in ROS 2. Imagine it as a Lego brick in your robot’s software architecture. Each package contains a specific piece of functionality or capability, like motor control, sensor processing, or communication with other systems.

Remember, just like Legos, you can combine multiple ROS 2 packages to create complex robot functionalities. Each package plays its specific role, and together they build the complete software system for your robot.

The official instructions for creating a package are here, but I will walk you through the entire process, step by step.

Let’s get started!

Prerequisites

Directions

Open a terminal, and type these commands (note: we are using the Apache 2.0 license, but you can remove that piece if you want):

cd ~/ros2_ws/src
ros2 pkg create --build-type ament_cmake --license Apache-2.0 cobot_arm_examples

Now let’s build our new package:

cd ~/ros2_ws
colcon build 

Let’s see if our new package is recognized by ROS 2.

Either open a new terminal window or source the bashrc file like this:

source ~/.bashrc
ros2 pkg list

You can see the newly created package right there at the top.

8-cobot-arm-examples

Install Useful Packages (Optional)

In a month or so, I will begin building a robotic arm. The package in this tutorial will serve as the foundation for the ROS 2 software.

Let’s install some useful packages that will help us along the way.

Begin by installing a tool called Terminator. Terminator will enable you to have multiple terminal panes within a single interface.

Open a terminal window, and type the following commands:

sudo apt-get update -y
sudo apt-get upgrade -y
sudo apt-get install terminator

To open terminator, you can either click the 9 dots in the bottom left of your Desktop and search for “terminator”….or you can type terminator in a regular terminal window.

You can use CTRL + Shift + E or CTRL + Shift + O to split the terminal window into different panels.

Let’s install some useful ROS 2 packages. Open a terminal window, and type the following:

sudo apt-get install ros-$ROS_DISTRO-gazebo-ros
sudo apt-get install ros-$ROS_DISTRO-gazebo-ros2-control
sudo apt-get install ros-$ROS_DISTRO-joint-state-publisher-gui
sudo apt-get install ros-$ROS_DISTRO-moveit
sudo apt-get install ros-$ROS_DISTRO-xacro
sudo apt-get install ros-$ROS_DISTRO-ros2-control
sudo apt-get install ros-$ROS_DISTRO-ros2-controllers
sudo apt-get install libserial-dev
sudo apt-get install python3-pip
pip install pyserial

If you want to use Amazon Alexa Voice Assistant down the road to control your robotic arm, install the following:

pip install ask-sdk
pip install flask
pip install flask-ask-sdk

Configure Colcon

colcon is the primary command-line tool for building, testing, and installing ROS packages.

In your terminal window, type the following command:

echo "source /usr/share/colcon_argcomplete/hook/colcon-argcomplete.bash" >> ~/.bashrc

That’s it! Keep building!