rrbot_base.launch.py

# Copyright 2021 Stogl Robotics Consulting UG (haftungsbeschränkt)
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument, RegisterEventHandler
from launch.conditions import IfCondition
from launch.event_handlers import OnProcessExit
from launch.substitutions import Command, FindExecutable, LaunchConfiguration, PathJoinSubstitution

from launch_ros.actions import Node
from launch_ros.substitutions import FindPackageShare


def generate_launch_description():
    # Declare arguments
    declared_arguments = []
    declared_arguments.append(
        DeclareLaunchArgument(
            "runtime_config_package",
            default_value="ros2_control_demo_bringup",
            description='Package with the controller\'s configuration in "config" folder. \
        Usually the argument is not set, it enables use of a custom setup.',
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "controllers_file",
            default_value="rrbot_controllers.yaml",
            description="YAML file with the controllers configuration.",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "description_package",
            default_value="rrbot_description",
            description="Description package with robot URDF/xacro files. Usually the argument \
        is not set, it enables use of a custom description.",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "description_file",
            description="URDF/XACRO description file with the robot.",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "prefix",
            default_value='""',
            description="Prefix of the joint names, useful for \
        multi-robot setup. If changed than also joint names in the controllers' configuration \
        have to be updated.",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "use_gazebo",
            default_value="false",
            description="Start robot in Gazebo simulation.",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "use_fake_hardware",
            default_value="true",
            description="Start robot with fake hardware mirroring command to its states.",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "fake_sensor_commands",
            default_value="false",
            description="Enable fake command interfaces for sensors used for simple simulations. \
            Used only if 'use_fake_hardware' parameter is true.",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "slowdown", default_value="3.0", description="Slowdown factor of the RRbot."
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "robot_controller",
            default_value="forward_position_controller",
            description="Robot controller to start.",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "start_rviz",
            default_value="true",
            description="Start RViz2 automatically with this launch file.",
        )
    )

    # Initialize Arguments
    runtime_config_package = LaunchConfiguration("runtime_config_package")
    controllers_file = LaunchConfiguration("controllers_file")
    description_package = LaunchConfiguration("description_package")
    description_file = LaunchConfiguration("description_file")
    prefix = LaunchConfiguration("prefix")
    use_gazebo = LaunchConfiguration("use_gazebo")
    use_fake_hardware = LaunchConfiguration("use_fake_hardware")
    fake_sensor_commands = LaunchConfiguration("fake_sensor_commands")
    slowdown = LaunchConfiguration("slowdown")
    robot_controller = LaunchConfiguration("robot_controller")
    start_rviz = LaunchConfiguration("start_rviz")

    # Get URDF via xacro
    robot_description_content = Command(
        [
            PathJoinSubstitution([FindExecutable(name="xacro")]),
            " ",
            PathJoinSubstitution(
                [FindPackageShare(description_package), "urdf", description_file]
            ),
            " ",
            "prefix:=",
            prefix,
            " ",
            "use_gazebo:=",
            use_gazebo,
            " ",
            "use_fake_hardware:=",
            use_fake_hardware,
            " ",
            "fake_sensor_commands:=",
            fake_sensor_commands,
            " ",
            "slowdown:=",
            slowdown,
        ]
    )
    robot_description = {"robot_description": robot_description_content}

    robot_controllers = PathJoinSubstitution(
        [
            FindPackageShare(runtime_config_package),
            "config",
            controllers_file,
        ]
    )
    rviz_config_file = PathJoinSubstitution(
        [FindPackageShare(description_package), "config", "rrbot.rviz"]
    )

    control_node = Node(
        package="controller_manager",
        executable="ros2_control_node",
        parameters=[robot_description, robot_controllers],
        output="both",
    )
    robot_state_pub_node = Node(
        package="robot_state_publisher",
        executable="robot_state_publisher",
        output="both",
        parameters=[robot_description],
    )
    rviz_node = Node(
        package="rviz2",
        executable="rviz2",
        name="rviz2",
        output="log",
        arguments=["-d", rviz_config_file],
        condition=IfCondition(start_rviz),
    )

    joint_state_broadcaster_spawner = Node(
        package="controller_manager",
        executable="spawner",
        arguments=["joint_state_broadcaster", "--controller-manager", "/controller_manager"],
    )

    robot_controller_spawner = Node(
        package="controller_manager",
        executable="spawner",
        arguments=[robot_controller, "-c", "/controller_manager"],
    )

    # 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],
        )
    )

    # Delay start of robot_controller after `joint_state_broadcaster`
    delay_robot_controller_spawner_after_joint_state_broadcaster_spawner = RegisterEventHandler(
        event_handler=OnProcessExit(
            target_action=joint_state_broadcaster_spawner,
            on_exit=[robot_controller_spawner],
        )
    )

    nodes = [
        control_node,
        robot_state_pub_node,
        joint_state_broadcaster_spawner,
        delay_rviz_after_joint_state_broadcaster_spawner,
        delay_robot_controller_spawner_after_joint_state_broadcaster_spawner,
    ]

    return LaunchDescription(declared_arguments + nodes)