localization_launch.py

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# Copyright (c) 2018 Intel Corporation
#
# 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.
 
import os
 
from ament_index_python.packages import get_package_share_directory
 
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument, SetEnvironmentVariable
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node
from nav2_common.launch import RewrittenYaml
 
 
def generate_launch_description():
    # Get the launch directory
    bringup_dir = get_package_share_directory("nav2_bringup")
 
    namespace = LaunchConfiguration("namespace")
    map_yaml_file = LaunchConfiguration("map")
    use_sim_time = LaunchConfiguration("use_sim_time")
    autostart = LaunchConfiguration("autostart")
    params_file = LaunchConfiguration("params_file")
    lifecycle_nodes = ["map_server", "amcl"]
 
    # Map fully qualified names to relative ones so the node's namespace can be prepended.
    # In case of the transforms (tf), currently, there doesn't seem to be a better alternative
    # https://github.com/ros/geometry2/issues/32
    # https://github.com/ros/robot_state_publisher/pull/30
    # TODO(orduno) Substitute with `PushNodeRemapping`
    #              https://github.com/ros2/launch_ros/issues/56
    remappings = [("/tf", "tf"), ("/tf_static", "tf_static")]
 
    # Create our own temporary YAML files that include substitutions
    param_substitutions = {"use_sim_time": use_sim_time, "yaml_filename": map_yaml_file}
 
    configured_params = RewrittenYaml(
        source_file=params_file,
        root_key=namespace,
        param_rewrites=param_substitutions,
        convert_types=True,
    )
 
    return LaunchDescription(
        [
            # Set env var to print messages to stdout immediately
            SetEnvironmentVariable("RCUTILS_LOGGING_BUFFERED_STREAM", "1"),
            DeclareLaunchArgument(
                "namespace", default_value="", description="Top-level namespace"
            ),
            DeclareLaunchArgument(
                "map",
                default_value=os.path.join(bringup_dir, "maps", "turtlebot3_world.yaml"),
                description="Full path to map yaml file to load",
            ),
            DeclareLaunchArgument(
                "use_sim_time",
                default_value="false",
                description="Use simulation (Gazebo) clock if true",
            ),
            DeclareLaunchArgument(
                "autostart",
                default_value="true",
                description="Automatically startup the nav2 stack",
            ),
            DeclareLaunchArgument(
                "params_file",
                default_value=os.path.join(bringup_dir, "params", "nav2_params.yaml"),
                description="Full path to the ROS2 parameters file to use",
            ),
            Node(
                package="nav2_map_server",
                executable="map_server",
                name="map_server",
                output="screen",
                parameters=[configured_params],
                remappings=remappings,
            ),
            Node(
                package="nav2_amcl",
                executable="amcl",
                name="amcl",
                output="screen",
                parameters=[configured_params],
                remappings=remappings,
            ),
            Node(
                package="nav2_lifecycle_manager",
                executable="lifecycle_manager",
                name="lifecycle_manager_localization",
                output="screen",
                parameters=[
                    {"use_sim_time": use_sim_time},
                    {"autostart": autostart},
                    {"node_names": lifecycle_nodes},
                ],
            ),
        ]
    )