official guide: https://docs.nav2.org/setup_guides/odom/setup_odom.html

TODO: add gazebo portion

ROS2 control 

  sudo apt install ros-humble-ros2-control ros-humble-ros2-controllers ros-foxy-humble-ros2-control
sudo apt-get install libserialport-dev

Good resource that explains ROS2 control: https://articulaandtedrobotics.xyz/tutorials/mobile-robot/applications/ros2_control-concepts

Nodes we are adding:

control_node
robot_controller_spawner
joint_state_broadcaster

add to ros2 control to urdf

Add control setting file in config folder

my_controllers.yaml

image.png

update setup.py and run 

  import os
from glob import glob

from setuptools import find_packages, setup

package_name = 'mbot_pkg'

setup(
    name=package_name,
    version='0.0.0',
    packages=find_packages(exclude=['test']),
    data_files=[
        ('share/ament_index/resource_index/packages',
            ['resource/' + package_name]),
        ('share/' + package_name, ['package.xml']),
        (os.path.join('share', package_name, 'urdf'), glob('urdf/*.urdf')),
        (os.path.join('share', package_name, 'rviz'), glob('rviz/*.rviz*')),
        (os.path.join('share', package_name), glob('launch/*launch.[pxy][yma]*')),
        (os.path.join('share', package_name, 'config'), glob('config/*.yaml*')),
    ],

update display.launch.py file

TODO:

  import launch
from launch.substitutions import Command, LaunchConfiguration
import launch_ros
import os

def generate_launch_description():
    pkg_share = launch_ros.substitutions.FindPackageShare(package='mbot_pkg').find('mbot_pkg')
    default_model_path = os.path.join(pkg_share, 'urdf/mbot_description.urdf')
    default_rviz_config_path = os.path.join(pkg_share, 'rviz/urdf_config.rviz')
    robot_controllers = os.path.join(pkg_share, "config/my_controllers.yaml")


    robot_state_publisher_node = launch_ros.actions.Node(
        package='robot_state_publisher',
        executable='robot_state_publisher',
        parameters=[{'robot_description': Command(['xacro ', LaunchConfiguration('model')])}]
    )
    joint_state_publisher_node = launch_ros.actions.Node(
        package='joint_state_publisher',
        executable='joint_state_publisher',
        name='joint_state_publisher',
        arguments=[default_model_path], #Add this line
        #parameters=[{'robot_description': Command(['xacro ', default_model_path])}],  #Remove this line
        #condition=launch.conditions.UnlessCondition(LaunchConfiguration('gui'))  #Remove this line
    )
    joint_state_publisher_gui_node = launch_ros.actions.Node(
        package='joint_state_publisher_gui',
        executable='joint_state_publisher_gui',
        name='joint_state_publisher_gui',
        condition=launch.conditions.IfCondition(LaunchConfiguration('gui'))
    )
    rviz_node = launch_ros.actions.Node(
        package='rviz2',
        executable='rviz2',
        name='rviz2',
        output='screen',
        arguments=['-d', LaunchConfiguration('rvizconfig')],
    )

    control_node = launch_ros.actions.Node(
        package="controller_manager",
        executable="ros2_control_node",
        parameters=[
            {'robot_description': Command(['xacro ', default_model_path])}, #FIXME: this should not be here
            robot_controllers],
        output="both",
        remappings=[
            ("/diffbot_base_controller/cmd_vel", "/cmd_vel"),
        ]
    )
    robot_controller_spawner = launch_ros.actions.Node(
        package="controller_manager",
        executable="spawner",
        arguments=["diffbot_base_controller", "--param-file", robot_controllers],
    )

    # Delay start of joint_state_broadcaster after `robot_controller`
    # TODO(anyone): This is a workaround for flaky tests. Remove when fixed.
    delay_joint_state_broadcaster_after_robot_controller_spawner = RegisterEventHandler(
        event_handler=OnProcessExit(
            target_action=robot_controller_spawner,
            on_exit=[joint_state_broadcaster_spawner],
        )
    )
    # Delay rviz start after `joint_state_broadcaster`
    delay_rviz_after_joint_state_broadcaster_spawner = RegisterEventHandler(
        event_handler=OnProcessExit(
            target_action=joint_state_broadcaster_spawner,
            on_exit=[rviz_node],
        )
    )

    return launch.LaunchDescription([
        #launch.actions.DeclareLaunchArgument(name='gui', default_value='True',
        #                                    description='Flag to enable joint_state_publisher_gui'),
        launch.actions.DeclareLaunchArgument(name='model', default_value=default_model_path,
                                            description='Absolute path to robot urdf file'),
        launch.actions.DeclareLaunchArgument(name='rvizconfig', default_value=default_rviz_config_path,
                                            description='Absolute path to rviz config file'),
        joint_state_publisher_node,
        # joint_state_publisher_gui_node,
        robot_state_publisher_node,
        control_node,
        robot_controller_spawner,
        
                delay_joint_state_broadcaster_after_robot_controller_spawner,
        delay_rviz_after_joint_state_broadcaster_spawner,
        #rviz_node
    ])

if you have a pi pico and RPLidar then this part applies to you

pi pico pkg

pi_pico_diff_pkg.zip

image.png

run:

  colcon build --symlink-install
ros2 launch mbot_pkg display.launch.py

Note: if your robot does not connect to your WSL go back to:

link_to_page

lidar

update the urdf 

    <link name="lidar_link">
    <inertial>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <mass value="0.125" />
      <inertia ixx="0.001" ixy="0" ixz="0" iyy="0.001" iyz="0" izz="0.001" />
    </inertial>

    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry>
        <cylinder radius="0.0508" length="0.055" />
      </geometry>
    </collision>

    <visual>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry>
        <cylinder radius="0.0508" length="0.055" />
      </geometry>
    </visual>
  </link>

  <joint name="lidar_joint" type="fixed">
    <parent link="base_link" />
    <child link="lidar_link" />
    <origin xyz="0.0416 0 0.12" rpy="0 0 ${pi}" />
  </joint>

update launch file 

      lidar_node = launch_ros.actions.Node(
        package='sllidar_ros2',
        executable='sllidar_node',
        name='sllidar_node',
        parameters=[{'channel_type': 'serial',
                     'serial_port': '/dev/ttyUSB0',
                     'serial_baudrate': 115200,
                     'frame_id': 'lidar_link',#'laser',
                     'inverted': False,
                     'angle_compensate': True,
                     'scan_mode': 'Boost'}],
        output='screen')

    return launch.LaunchDescription([
        #launch.actions.DeclareLaunchArgument(name='gui', default_value='True',
        #                                    description='Flag to enable joint_state_publisher_gui'),
        launch.actions.DeclareLaunchArgument(name='model', default_value=default_model_path,
                                            description='Absolute path to robot urdf file'),
        launch.actions.DeclareLaunchArgument(name='rvizconfig', default_value=default_rviz_config_path,
                                            description='Absolute path to rviz config file'),
        joint_state_publisher_node,
        # joint_state_publisher_gui_node,
        robot_state_publisher_node,

        control_node,
        robot_controller_spawner,

        lidar_node,

        delay_joint_state_broadcaster_after_robot_controller_spawner,
        delay_rviz_after_joint_state_broadcaster_spawner,
        # rviz_node
    ])

package link: https://github.com/Slamtec/sllidar_ros2

run guide: https://github.com/robopeak/rplidar_ros/wiki

  sudo chmod 777 /dev/ttyUSB0

image.png

to debug run:

  ros2 launch sllidar_ros2 view_sllidar_a1_launch.py