Getting Started with ROS

For this workshop specifically:

You don’t have to worry about the whole process of setting up ROS, installing the code base, getting environment setup, sourcing the right files, etc. as the web software we will be using, ConstructSim, gives you the space pre-built with everything ready to go. Start from the note after Step 2.

Many visualization tools from this workshop will load and run on Guacamole inside your ROSject, which is a Remote Desktop that emulates the software. This will be more clear in a bit.

Though ROS1 exists, upgrades for ROS1 have stopped and ROS2 is being continuously improved with newer versions released every year. Different ROS2 versions lose support over time so it is important to keep everything up-to-date. However, switching between versions of ROS2 is very easy. Switching from ROS1 to ROS2 or vice versa takes a very very very long time.

System Requirements

To get started with ROS, you will need to have a UNIX-shell based operating system, such as Ubuntu, Mac OS, Debian, Arch Linux, etc. (though there are workarounds for Windows, about 99% of support and development is for and on UNIX-based operating systems). Ubuntu is the most widely used OS for ROS development.

Ubuntu Version	ROS2 Version	Support
18.04	Rolling Ridley	Rolling Dev Release, No longer supported
20.04	Foxy Fitzroy	Support will stop this year
20.04	Galactic Geochelone	No longer Supported
22.04	Humble Hawksbill	Current Most Active Support
22.04	Iron Irwini	Latest, Recent Active Support

Installing ROS2 Humble

No-one explains ROS setup better than ROS docs themselves, so if you ever have to do so:

Ubuntu (Debian packages) — ROS 2 Documentation: Humble documentation

NOTE

IF YOU ARE USING ConstructSim, (which will be the case if you are live for the workshop)

Follow this to open your ROSject (ROS Project on ConstructSim) for this workshop.

Login at https://app.theconstructsim.com/login

Navigate to My ROSjects under Develop in the left tabs list.

Create New ROSject → Select ROS2 Humble as your ROS Distro, Give it a name and a Description and Run it

Your ROSject should now be running - notice the timer in the bottom (it should be 07:59 or close to that if this is your first time running it today), that’s the amount of time you have left to work on that ROSject today. ConstructSim ROSjects are a free service and they limit how much you can use their servers.

Checking Install - Running basic Examples

Now that you have ROS installed, you want to make sure that the install happened the correct way and that you can use ROS packages as expected.

Before you start, let’s update the installation candidate that you’re working with.

sudo apt update

First, you want to source the ROS environment to make sure it exists:

source /opt/ros/jazzy/setup.bash

This should just run with no output and errors.

Now enter just ros2 in the terminal and check if shows a bunch of ros2 information and commands. Just typing ros2 should give you the following output in the terminal:

usage: ros2 [-h] [--use-python-default-buffering] Call `ros2 <command> -h` for more detailed usage. ...
ros2 is an extensible command-line tool for ROS 2.options:
  -h, --help            show this help message and exit
  --use-python-default-buffering
                        Do not force line buffering in stdout and instead use the python default buffering, which might
                        be affected by PYTHONUNBUFFERED/-u and depends on whatever stdout is interactive or not

Commands:
  action     Various action related sub-commands
  bag        Various rosbag related sub-commands
  component  Various component related sub-commands
  control    Various control related sub-commands
  daemon     Various daemon related sub-commands
  doctor     Check ROS setup and other potential issues
  interface  Show information about ROS interfaces
  launch     Run a launch file
  lifecycle  Various lifecycle related sub-commands
  multicast  Various multicast related sub-commands
  node       Various node related sub-commands
  param      Various param related sub-commands
  pkg        Various package related sub-commands
  run        Run a package specific executable
  security   Various security related sub-commands
  service    Various service related sub-commands
  topic      Various topic related sub-commands
  wtf        Use `wtf` as alias to `doctor`

  Call `ros2 <command> -h` for more detailed usage.

In your current terminal, enter:

ros2 run demo_nodes_cpp talker

Leave that terminal open, now open a new terminal, and enter:

ros2 run demo_nodes_py listener

You should see the talker saying that it’s Publishing messages and the listener saying Iheard those messages. (Subscribing)

Similarly, try the following:

Terminal 1:

ros2 run turtlesim turtlesim_node
# this should open turtlesim on a pop-up window of Guacamole

Terminal 2:

ros2 run turtlesim turtle_teleop_key
# when your cursor is in this terminal and you use your arrow keys,
# you should be able to control the turtle in 2D

Create package:

ros2 pkg create --build-type ament_python <pkg_name>

NOTE