nav2-keepout-zone

Navigation in ROS2 with Nav2 introduced a lot of new features and possibilities. The goal of this assignment is to explore and test the new feature of navigating in a known environment while avoiding user-defined keep out areas.

Installation

This package requires the following dependencies:

sudo apt install ros-<ros2-distro>-slam-toolbox

sudo apt install ros-<distro>-navigation2 ros-<distro>-nav2-bringup '~ros-<distro>-turtlebot3-.*'

Once all the dependencies are met, the packge could be cloned and compiled as it is represented:

mkdir -p colcon_ws/src

cd colcon_ws/src

git clone https://github.com/aliy98/nav2-keepout-zone

cd colcon_ws

colcon build --symlink-install

source install/setup.bash

Simulation Environment

Webots2023a is a simulation software, in which this project was done. It is compliant with ROS2, and provides the TIAGo robot urdf model, which is chosen to be used in this project.

The following figure, provides an overview from the simulation environment of this project:

Mapping

The first step of this experiment, consists of creating a map of the indoor environemnt. slam_toolbox provides an online synchronous mapping ROS node, using the following command:

ros2 launch slam_toolbox online_async_launch.py

which was used in this project along with Nav2 applications. The following command would bringup navigation:

ros2 launch nav2_bringup navigation_launch.py

This would help us to define goal points during slam. In order to launch these two nodes along with the simulation environment, the slam_launch.py file is provided in this package, which takes an world file as an argument:

ros2 launch sofar_assignment slam_launch.py world:=default.wbt

Here is an overview of the mapping process:

The UML component diagram of this part is shown in following figure:

Creating keepout filter masks:

Once the map is built, the keepout areas could be drwan on the map.pgm file and saved as the mask filter. The corresponding mask yaml file mode has to be chosen as scale, so that the occupancy grids of each area, would be defined with a certain level of occupancy. The follwoing figures show a sample of keepout filter mask along with the original map file:

Navigation and path planning

In the last step of this project, the navigation and path planning part is done, considering the keepout zones. The provided nav_launch.py in this package would bring the simulation environment along with navigation2 applications such as map_server, costmap_filter_info_server and life_cycle_manager. The following command represents the arguments that this launch file requires:

ros2 launch sofar_assignment nav_launch.py world:=default.wbt map:=src/nav2-keepout-zone/resource/map.yaml params_file:=src/nav2-keepout-zone/resource/nav2_params.yaml keepout_params_file:=src/nav2-keepout-zone/resource/keepout_params.yaml mask:=src/nav2-keepout-zone/resource/keepout_mask.yaml

The UML component diagram of this part is shown in following figure:

Authors and Contacts

• Ali Yousefi
• email: aliyousefi98@outlook.com