ROS Getting Started Notes

This tutorial is based on ROS2 Foxy and Ubuntu 20.04.

Installing the ROS Environment

Setting UTF-8 Encoding

sudo locale-gen en_US en_US.UTF-8
sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8
export LANG=en_US.UTF-8

Setting Software Sources

sudo apt update && sudo apt install curl gnupg2 lsb-release
curl -s https://raw.githubusercontent.com/ros/rosdistro/master/ros.asc | sudo apt-key add -

sudo sh -c 'echo "deb [arch=$(dpkg --print-architecture)] http://packages.ros.org/ros2/ubuntu $(lsb_release -cs) main" > /etc/apt/sources.list.d/ros2-latest.list'

Installing ROS2

sudo apt update
sudo apt install ros-foxy-desktop

Setting Environment Variables

source /opt/ros/foxy/setup.bash

Installing Auto-Completion Tool

sudo apt install python3-argcomplete

Testing After Successful Installation

Run the Talker:

source /opt/ros/foxy/setup.bash
ros2 run demo_nodes_cpp talker

Open a new terminal window and run the Listener:

source /opt/ros/foxy/setup.bash
ros2 run demo_nodes_py listener

Uninstalling ROS (If Needed)

sudo apt remove ros-foxy-* && sudo apt autoremove

Afterward, check ~/.bashrc and the /opt/ directory for the presence of ROS folders.

Configuring ROS2 Environment

source /opt/ros/foxy/setup.bash

Check the configuration after setting:

printenv | grep -i ROS

Turtle Simulator

Installation

sudo apt update
sudo apt install ros-foxy-turtlesim

Check if the installation was successful:

ros2 pkg executables turtlesim

Launching the Turtle Simulator

ros2 run turtlesim turtlesim_node

To make the turtle move, open a new terminal window and enter the following command:

ros2 run turtlesim turtle_teleop_key

Follow the prompts in the terminal to control the turtle.

Installing rqt Tools

sudo apt update
sudo apt install ~nros-foxy-rqt*

Launching rqt Tools

First, ensure that a turtle is running in the background. In the terminal, enter:

rqt

Launch the rqt tool and, in sequence, open Plugins > Services > Service Caller. Click the refresh button to see all services.

Select the /spawn service, enter the turtle's name (e.g., 'GuaiGuai') and position to create another turtle. If you want to modify its trajectory's color and shape, you can adjust the content of the /set_pen service.

To control the movement of the newly generated turtle, you can use the following command (please note the turtle's name):

ros2 run turtlesim turtle_teleop_key --ros-args --remap turtle1/cmd_vel:=guaiguai/cmd_vel

References and Acknowledgments

• ROS2 Beginner's Tutorial - 2. Installing ROS2 Foxy on Ubuntu 20.04
• ROS2 Beginner's Tutorial - 3. Setting Up the ROS2 Environment
• ROS2 Beginner's Tutorial - 4. Basic Usage of the Turtle Simulator

This post is translated using ChatGPT, please feedback if any omissions.