Navigation2¶

1. Overview¶

The ROS 2 Navigation System is the control system that enables a robot to autonomously reach a goal state, such as a specific position and orientation relative to a specific map. Given a current pose, a map, and a goal, such as a destination pose, the navigation system generates a plan to reach the goal, and outputs commands to autonomously drive the robot, respecting any safety constraints and avoiding obstacles encountered along the way.

2. Running the demo¶

The nav2_bringup package is an example bringup system for navigation2 applications.

Note

We recommend doing this on a Ubuntu 18.04 installation. We have build issues on 16.04. (see https://github.com/ros-planning/navigation2/issues/353)
This stack and ROS2 are still in heavy development and there are some bugs and stability issues being worked on, so please do not try this on a robot without taking heavy safety precautions. THE ROBOT MAY CRASH!
It is recommended to start with simulation using Gazebo before proceeding to run on a physical robot

2.1 Launch Navigation2 in simulation with Gazebo¶

Pre-requisites:¶

Gazebo installed on the system
gazebo_ros_pkgs for ROS2 installed on the system
A Gazebo world for simulating the robot (see Gazebo tutorials)
A map of that world saved to a map.pgm and map.yaml (see ROS Navigation tutorials)

Terminal 1: Config turtlebot3 and Gazebo simulation environment

Example: See turtlebot3_gazebo models for details.

source /opt/robot_devkit/robot_devkit_setup.bash
echo export GAZEBO_MODEL_PATH=$GAZEBO_MODEL_PATH:`ros2 pkg prefix turtlebot3_gazebo`/share/turtlebot3_gazebo/models/ >> ~/.bashrc
echo export TURTLEBOT3_MODEL=waffle >> ~/.bashrc
echo ROS_DOMAIN_ID=30 >> ~/.bashrc

view result at rviz2 and Gazebo

Terminal 2: Launch your robot in Gazebo

source /opt/robot_devkit/robot_devkit_setup.bash
source /opt/ros/dashing/local_setup.bash
ros2 launch turtlebot3_gazebo turtlebot3_world.launch.py

Terminal 3: Launch navigation2

source /opt/robot_devkit/robot_devkit_setup.bash
source /opt/ros/dashing/local_setup.bash
# Launch the nav2 system
ros2 launch turtlebot3_navigation2 navigation2.launch.py use_sim_time:=True autostart:=True \
map:=`ros2 pkg prefix turtlebot3_navigation2`/share/turtlebot3_navigation2/map/map.yaml

Note

In RViz:

You should see the map.
Hit the “Startup” button.
Localize the robot using “2D Pose Estimate” button.
Make sure all transforms from odom are present. (odom->base_link->base_scan)
Send the robot a goal using “Navigation2 Goal” button. Note: this uses a ROS2 Action to send the goal, and a pop-up window will appear on your screen with a ‘cancel’ button if you wish to cancel.

To view the robot model in RViz:

Add “RobotModel”, set “Description Source” with “File”, set “Description File” with the name of the urdf file for your robot (example: turtlebot3_burger.urdf)”

2.2 Launch Navigation2 on a Robot¶

Pre-requisites:¶

Run SLAM or Cartographer with tele-op to drive the robot and generate a map of an area for testing first. The directions below assume this has already been done. If not, it can be done in ROS1 before beginning to install our code.
Publish all the transforms from your robot from base_link to base_scan

Terminal 1: Launch the robot

echo export TURTLEBOT3_MODEL=waffle >> ~/.bashrc
echo ROS_DOMAIN_ID=30 >> ~/.bashrc
source /opt/robot_devkit/robot_devkit_setup.bash
ros2 launch turtlebot3_bringup robot.launch.py

Terminal 2: Launch the code using this launch file and your map.yaml

source /opt/robot_devkit/robot_devkit_setup.bash
source /opt/ros/dashing/local_setup.bash
ros2 launch nav2_bringup nav2_bringup_launch.py map:=<full/path/to/map.yaml>

Terminal 3: Run RVIZ

ros2 run rviz2 rviz2 -d $(ros2 pkg prefix nav2_bringup)/share/nav2_bringup/launch/nav2_default_view.rviz

In RVIZ2:

Make sure all transforms from odom are present. (odom->base_link->base_scan)

Click 2D Pose Estimate button in the menu bar and then point exact pose of TurtleBot3 on the map.

If TurtleBot3 is close to a costmap or nearby the costmap map, click Navigation2 Goal button in the menu bar and then point goal pose on the map.

3. Known issues¶

This stack and ROS2 are still in heavy development and there are some bugs and stability issues being worked on, so please do not try this on a robot without taking heavy safety precautions. THE ROBOT MAY CRASH!
For a current list of known issues, see https://github.com/ros-planning/navigation2/issues.

4. ToDo¶

Add additional maps and examples.
Add instructions for running navigation2 with SLAM.