Robotics Competition
2023-24

Mapping - Using slam-toolbox

1. First pull the latest repo of `eYRC-2023_Cosmo_Logistic` in your workspace.

Check for the pkg ebot_nav2 and below is the file structure.

2. Check for the `slam-toolbox` installation.

    ros2 pkg list | grep slam_toolbox

You should get slam_toolbox as output, which means we are good to go.
If not, install slam_toolbox using,

sudo apt install ros-humble-slam-toolbox

3. Set the parameters for `slam-toolbox` in file `mapper_params_online_async.yaml` in dir `/ebot_nav2/config/`.

    # ROS Parameters
    odom_frame: odom   #>> /odom is our odometry frame
    map_frame: map   #>> wrt "map" frame we will be getting the map
    base_frame: base_footprint  #>> eBot base_frame is base_footprint, you can check it using `ros2 run tf2_tools view_frames`
    scan_topic: /scan  #>> LiDAR data is on this topic
    mode: mapping #localization  #>> Currently we will be mapping using slam-toolbox.

All the params are set.

4. Loading the `mapper_params_online_async.yaml` and adding the `slam_toolbox` node in out `ebot_bringup_launch.py` launch file in dir `/ebot_nav2/launch/`, it's already added in launch file.

	# Loading the params
    declare_mapper_online_async_param_cmd = DeclareLaunchArgument(
        'async_param',
        default_value=os.path.join(ebot_nav2_dir, 'config', 'mapper_params_online_async.yaml'),
        description='Set mappers online async param file')

	# Adding slam-toolbox, with online_async_launch.py
    mapper_online_async_param_launch = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(
            os.path.join(get_package_share_directory('slam_toolbox'), 'launch', 'online_async_launch.py'),
        ),
        launch_arguments=[('slam_params_file', LaunchConfiguration('async_param'))],
    )

To know more about check here

4. Just add this as the object of `LaunchDescription()` in the same launch file, in the last.

	ld.add_action(declare_mapper_online_async_param_cmd)
    ld.add_action(mapper_online_async_param_launch)

Just save it

5. Launch the `ebot_gazebo_launch.py`, `teleop` and `ebot_bringup_launch.py`

	ros2 launch ebot_description ebot_gazebo_launch.py

	ros2 run teleop_twist_keyboard teleop_twist_keyboard

	ros2 launch ebot_nav2 ebot_bringup_launch.py

You will get output like this,

Now keep maving the eBot using teleop_twist_keyboard in the warehouse and grab the whole map perfectly.

Hint: GO SLOW ! Next step is very important