A ROS 2 launch file that works with the Crazyswarm2 ROS 2 crazyflie server and the ROS 2 merge mapping example

swarm_mapping_launch.py

import os

from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch_ros.actions import Node
import yaml


def generate_launch_description():

    # load crazyflies
    crazyflies_yaml = os.path.join(
        get_package_share_directory('crazyflie'),
        'config',
        'crazyflies.yaml')

    with open(crazyflies_yaml, 'r') as ymlfile:
        crazyflies = yaml.safe_load(ymlfile)

    server_params = crazyflies

    # robot description
    urdf = os.path.join(
        get_package_share_directory('crazyflie'),
        'urdf',
        'crazyflie_description.urdf')
    with open(urdf, 'r') as f:
        robot_desc = f.read()
    server_params['robot_description'] = robot_desc

    crazyflie_name = '/cf231'

    return LaunchDescription([
      # These nodes need https://github.com/IMRCLab/crazyswarm2
        Node(
            package='crazyflie',
            executable='crazyflie_server.py',
            name='crazyflie_server',
            output='screen',
            parameters=[server_params],
            #remappings=[
            #    ('/cf4/odom', '/cfcombi/odom'),
            #    ('/cf4/scan', '/cfcombi/scan'),
            #    ('/cf5/odom', '/cfcombi/odom'),
            #    ('/cf5/scan', '/cfcombi/scan'),
            #    ('/cf6/odom', '/cfcombi/odom'),
            #    ('/cf6/scan', '/cfcombi/scan'),
            #]
        ),
        Node(
            package='crazyflie',
            executable='vel_mux.py',
            name='vel_mux',
            output='screen',
            parameters=[{'hover_height': 0.3},
                        {'incoming_twist_topic': '/cmd_vel'},
                        {'robot_prefix': 'cf4'}]
        ),
        Node(
            package='crazyflie',
            executable='vel_mux.py',
            name='vel_mux',
            output='screen',
            parameters=[{'hover_height': 0.4},
                        {'incoming_twist_topic': '/cmd_vel'},
                        {'robot_prefix': 'cf5'}]
        ),
        Node(
            package='crazyflie',
            executable='vel_mux.py',
            name='vel_mux',
            output='screen',
            parameters=[{'hover_height': 0.5},
                        {'incoming_twist_topic': '/cmd_vel'},
                        {'robot_prefix': 'cf6'}]
        ),
        Node(
            package='crazyflie',
            executable='simple_mapper_multiranger.py',
            name='simple_mapper_multiranger',
            output='screen',
            parameters=[
                {'robot_prefix': 'cf4'}]
        ),
        Node(
            package='crazyflie',
            executable='simple_mapper_multiranger.py',
            name='simple_mapper_multiranger',
            output='screen',
            parameters=[
                {'robot_prefix': 'cf5'}]
        ),
        Node(
            package='crazyflie',
            executable='simple_mapper_multiranger.py',
            name='simple_mapper_multiranger',
            output='screen',
            parameters=[
                {'robot_prefix': 'cf6'}]
        ),
      # these node need: https://github.com/abdulkadrtr/mapMergeForMultiRobotMapping-ROS2
        Node(
            package='merge_map',
            executable='merge_map',
            output='screen',
            remappings=[
                ("/map1", "/cf6/map"),
                ("/map2", "/cf5/map"),
                ("/merge_map", "/map12")
            ],
        ),
        Node(
            package='merge_map',
            executable='merge_map',
            output='screen',
            remappings=[
                ("/map1", "/map12"),
                ("/map2", "/cf4/map"),
           ],
        ),
    ])