ROS2 Gazebo Tutorials

This is a basic tutorial on obstacle avoidance using turtlebot3 and ROS2. Firstly, install all the dependencies required

Setting up and sourcing ROS

You will have to install ROS2 first, the instructions for which can be found on http://docs.ros.org/en/foxy/Installation.html. We will be using ROS2 Foxy for the purposes of this tutorial.

First, source your ROS2 environment:

source /opt/ros/foxy/setup.bash

Alternatively, you can add this to your system's .bashrc file to avoid sourcing ROS2 underlay each time a new terminal is opened:

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

Setting up the project

Now, create a workspace to work with new packages. This is done so that you don't have to build all the packages each time you try building a new package.

mkdir -p <your_dir>/ros2_ws/src
cd ros2_ws/src/

Download the code from the repository:

git clone git@github.com:Bhargav-Soothram/gazebo-tutorials.git

Now rename the package using (this is for build purposes)

mv gazebo_tutorials simple_walker

Building the package

It is time to build the package! But before that, check if you have all the dependencies using resdep before going ahead:

rosdep install -i --from-path src --rosdistro foxy -y

Build the package:

cd ..
colcon build --packages-select simple_walker

Running the package

Open a new terminal, navigate to ros2_ws, and source the setup files:

. install/setup.bash

Using Launch files

We can use launch files to 'spin' multiple nodes at once with arguments passed to each of them. The arguments provided are the parameters to the nodes being executed. To run the obstacle avoidance simulation, use the following command:

ros2 launch simple_walker simple_walker.launch record:=<True/False>

record #whether or not to record a rosbag file for the current execution (Set to False by default)

Inspecting and playing the rosbag file

Open a new terminal, navigate to ros2_ws, and source the setup files as we did before.

For inspection:

ros2 bag info <rosbag_file>

*(rosbag_file is a .bag file)

To play a recorded rosbag file:

ros2 bag play <rosbag_file>

_launch.py: Runs a publisher and subsriber with the given message
_launch_bag.py: Inherits the functionality of _launch.py and adds the option to record rosbags

latent-pixel / gazebo-tutorials