ROS 2 Navigation and SLAM with Nav2 and Gazebo Harmonic

📖 Related Blog Post: For a detailed walkthrough, check out the companion article on Medium: 👉 Mastering ROS 2 Navigation: From SLAM Mapping to Autonomous Obstacle Avoidance

This blog post explains the architecture, challenges, and step-by-step setup for this project — ideal if you're new to Nav2, SLAM Toolbox, or working with Gazebo Harmonic!

Overview

This project utilizes Nav2 and SLAM Toolbox for robot navigation and obstacle avoidance in a simulated environment. The robot autonomously detects obstacles and adjusts its path to avoid collisions while leveraging Gazebo Harmonic for realistic simulations and ROS 2 Jazzy for communication and control.

Features

• Obstacle Avoidance: The robot automatically detects obstacles and adjusts its trajectory to avoid collisions.
• Simulation Environment: Uses Gazebo Harmonic for high-fidelity simulations.
• Visualization: RViz support for real-time sensor data and path visualization.

Requirements

Operating System:

• Ubuntu 24.04 (Recommended)

ROS Distribution:

• ROS 2 Jazzy

Simulator:

• Gazebo Harmonic

Installation

Add ROS 2 Jazzy Repository (if not already added)

If the ROS 2 Jazzy packages are not found, you might need to add the ROS 2 repository. Use the following commands:

sudo apt update
sudo apt install curl gnupg2 lsb-release
curl -sSL https://raw.githubusercontent.com/ros/rosdistro/master/ros.key | sudo apt-key add -
sudo sh -c 'echo "deb [arch=amd64] http://packages.ros.org/ros2/ubuntu $(lsb_release -cs) main" > /etc/apt/sources.list.d/ros2-latest.list'

Afterward, update your package lists:

sudo apt update

Install Required ROS 2 Packages

Make sure to install the following ROS 2 Jazzy packages:

sudo apt-get update
sudo apt install -y \   
   ros-jazzy-ros-gz \  
   ros-jazzy-ros-gz-bridge \  
   ros-jazzy-joint-state-publisher \  
   ros-jazzy-xacro \  
   ros-jazzy-teleop-twist-keyboard \  
   ros-jazzy-teleop-twist-joy \  
   ros-jazzy-nav2-bringup \  
   ros-jazzy-slam-toolbox \
   ros-jazzy-navigation2

Create a ROS 2 Workspace (if you don’t already have one)

mkdir -p ~/roscar/src
cd ~/roscar
colcon build --symlink-install

Clone This Repository into the Workspace

cd ~/roscar/src
git clone https://github.com/darshmenon/rosnav.git

(The repository will be cloned into a folder named rosnav.)

Build the Workspace

cd ~/roscar
colcon build --symlink-install

Source Your Workspace

source ~/roscar/install/setup.bash

Verify ROS 2 Packages Installation

Ensure that the ROS 2 packages are available and installed correctly. Use the following command to list installed packages:

ros2 pkg list | grep ros-gz
ros2 pkg list | grep teleop

Running Navigation and SLAM

Important Configuration Step

Before running Nav2 and SLAM, update the mapper_params_online_async.yaml file with the correct path to your map file. Replace the existing map_file_name entry with the path to your map location. For example:

map_file_name: /home/darsh/ros2/my_map_serial

This change should be made in src/diff_drive_robot-main/config/mapper_params_online_async.yaml.

Start Navigation with Nav2

To launch the navigation stack:

ros2 launch diff_drive_robot robot.launch.py

Once Nav2 is running, set the navigation goal pose in RViz.

Run SLAM and Generate a Map

To start SLAM and generate a map:

ros2 launch diff_drive_robot slam.launch.py

(SLAM must be running for Nav2 to work.)

Manual Robot Control

If you prefer manual control, use the keyboard teleoperation tool:

ros2 run teleop_twist_keyboard teleop_twist_keyboard

This allows you to control the robot using the arrow keys.

Goal Setting (Alternative Method)

Alternatively, you can modify robot.launch.py to comment out the navigation node and manually set navigation goals. Set your target destination directly in the navigation script navigation.py. For example, to set the goal at x = 5.0 and y = 4.0, modify the script:

   self.goal = [5.0, 4.0]  

Troubleshooting

If you encounter issues with missing ROS 2 packages like ros-jazzy-ros-gz, it’s possible the packages are not available through the default apt repository. In such cases:

1. Ensure the ROS 2 Jazzy repositories are properly added to your system.
2. If packages are missing, build from source by cloning the relevant repositories into your workspace.

Contributing

Feel free to contribute to this project by submitting issues or pull requests.