ROS2のlaunchファイルで引数を与える

実際のところ

• UFactory Lite6用ノード
• Joystick用ノード
• JoystickでUFactory Lite6を動かすpythonアプリ

の三つを起動する例を考えます。

from launch_ros.actions import Node
from launch.actions import DeclareLaunchArgument, ExecuteProcess
from launch.substitutions import LaunchConfiguration

def generate_launch_description():
    # デフォルトのパラメータ値を設定
    default_robot_ip_left = '192.168.1.XXX'
    default_hw_ns = 'left_lite6'
    default_dev_id = '/dev/input/js0'

    # Launch引数を宣言
    return LaunchDescription([
        DeclareLaunchArgument(
            'robot_ip_left',
            default_value=default_robot_ip
        ),

        DeclareLaunchArgument(
            'hw_ns_left',
            default_value=default_hw_ns
        ),

        DeclareLaunchArgument(
            'dev_left',
            default_value=default_dev_id
        ),

        # xarm_apiのドライバー起動
        Node(
            package='xarm_api',
            executable='lite6_driver.launch.py',
            arguments=['robot_ip:=' + LaunchConfiguration('robot_ip'), 'hw_ns:=' + LaunchConfiguration('hw_ns')],
            output='screen'
        ),

        # joy_linuxノードの起動
        Node(
            package='joy_linux',
            executable='joy_linux_node',
            arguments=['--ros-args', '-p', 'dev:=' + LaunchConfiguration('dev_did'), '--remap', 'joy:=/hand'],
            output='screen'
        ),
        # Pythonスクリプトの実行
        ExecuteProcess(
            cmd=['python3', 'dev_ws/joyapp.py'],
            output='screen'
        )
    ])