Software Challenge

This repository will act as a starting point for new developers in order to help them understand some of the fundamentals of ROS2 and Gazebo, and to guide the installation of the Ubuntu OS.

Ubuntu 20.04 installation guide

ROS2 and our robot's on-board computer (Nvidia TX2) use on a linux distribution to operate, for our development work we will be using Ubuntu 20.04 preferably dual booted alongside Windows. Developing in linux using a Mac machine is generally not recommended but if there is no option please follow the dual-booting instructions below using an Ubuntu 20.04 image or explore virtual box options.

For this tutorial, you'll need a blank, >4 GB stoarge USB stick.

For dual-booting: Different brands of computer may encounter manufacturer-specific blocks, please refer to the documentation relevant to your machine for solutions.

• Windows Subsystem for Linux (WSL) 2
  • This option has not been throughly tested, however ROS2 and other GUI applications can install and run successfully
  • The linked instructions require Windows 10 build 1903 or higher to install (check using 'winver'), follow the manual instructions to ensure WSL is upgraded
  • If you've installed Windows build 21364 or higher (check using the program, winver), you will be able to run GUI application autmatically, if you have not, continue with the next instruction
  • After enabling the kernel and installing Ubunutu 20.04, install VcXsrv
  • Start the service (XLanuch) and enter these configurations:
    • First screen: select "Multiple Windows", Display number = -1
    • Second Screen: select "Start no client"
    • Third Screen: check "Clipboard", uncheck "Native opengl", check "Disable Access Control"
    • Select finish
  • Finally, in your Ubuntu 20.04 terminal, run the command:

echo "export GAZEBO_IP=127.0.0.1" >> ~/.bashrc && echo "export DISPLAY=$(cat /etc/resolv.conf | grep nameserver | awk '{print $2}'):0 " >> ~/.bashrc && echo "export LIBGL_ALWAYS_INDIRECT=0" >> ~/.bashrc

• After a restart, you should now have a functional Ubuntu virtual machine, you can test your GUI by installing firefox (sudo apt-get install -y firefox) and running it with firefox

• Windows Instructions

  • Make bootable USB with Rufus
  • Note: BIOS can also be accessed by restarting using Recovery options menu in windows.

• Mac Instructions

Windows - Docker

There is a new option, to use Docker for development

• Install Docker
• Install WSL
• install VcXsrv
• Run docker pull hashaam1217/ubc_subbots:1.3
• Start the service (XLanuch) and enter these configurations:
  • First screen: select "Multiple Windows", Display number = -1
  • Second Screen: select "Start no client"
  • Third Screen: check "Clipboard", uncheck "Native opengl", check "Disable Access Control"
  • Select finish
• Run docker run -it --name ubc_subbots -e DISPLAY=host.docker.internal:0 -v /tmp/.X11-unix:/tmp/.X11-unix hashaam1217/ubc_subbots:1.3 in terminal as adminstrator
• To open another terminal connected to the same OS, run docker exec -it ubc_subbots /bin/bash
• It should be already installed with all tools neccessary to work with ROS2.
• This is a stateless system, you're changes are not saved so make you sure you push your changes to github before exiting

Saving your image (optional)

• If you want to save your image you can do it in a few steps.
• Use docker ps -a to view the last container you have opened.
• We can use docker commit [Your old container ID or name] [Name of the new image] to save our last workspace for future use.
• For example the name of the first container is "ubc_subbots". We can use docker commit ubc_subbots my_local_image to save your last container for future use.
• You will have to modify the run command like this: docker run -it -e DISPLAY=host.docker.internal:0 -v /tmp/.X11-unix:/tmp/.X11-unix my_local_image

Once Ubuntu is installed, you will need to install a preferred IDE. Some suggestions are listed below:

• Eclipse
• Clion (can be tedious to setup, requires an account)
• VS Code (strenuous setup but very powerful IDE)

Minor troubleshooting

• If you get: "docker: Error response from daemon: Conflict. The container name "/ubc_subbots" is already in use by container "ba09d34e252debcbbff86e893e2396195996d24a7aa4be900e704f67091e0a20". You have to remove (or rename) that container to be able to reuse that name. See 'docker run --help'." Run docker rm ubc_subbots

• If you get: "docker: error during connect: in the default daemon configuration on Windows, the docker client must be run with elevated privileges to connect: Post "http://%2F%2F.%2Fpipe%2Fdocker_engine/v1.24/containers/create": open //./pipe/docker_engine: The system cannot find the file specified. See 'docker run --help'." You might want to launch the docker app before you type in terminal commands.

Git command line tools

To use Git from the linux command line, follow the install here

ROS2 Installation

To install ROS2, follow the tutorial here, please install the desktop version.

Next, you will need to install the ROS2 build tools (Colcon). Please follow the guide here

Gazebo 11 Installation

Gazebo is a simulation environment which we will be using to test our robot's computer vision and control algorithms, use the "Default installation" option here to download the application and then run the command: "sudo apt install ros-foxy-gazebo-ros-pkgs" adapted from the instructions here to install the ROS2 plugins.

ROS2 Index

The ROS2 Index is the main source of information about the framework. To get a solid understanding of ROS2 concepts, follow along with all of the beginner tutorials here. It's reccomended to look through all of the intermediate and advanced tutorials as well as we will use concepts explained in these regularily.

The Challenge

Using the Turtlesim package, you will write a node that commands the turtle to perform a sine motion using the information available in the ROS2 wiki.

1. Open a new cmd prompt, clone this repository onto your machine and switch to the resulting folder.
2. Create a new branch using the convention, challenge/{your name}.
3. Inside this directory, create a folder named "src" (use cmd commands) and change directory to this folder.
4. Create a ROS 2 C++ package inside the repository named "challenge" with a node named "solution" (ROS2 tutorials refer to dev_ws/src, in your case this should be software-start-here/src).
5. Fill in your node so that it can command the turtlesim node to perform a sine motion.
6. Bonus Write a launch file to launch a turtlesim node and your node together.
7. push your node to Git and let Jake or Logan know that you've completed the challenge!