Hi there,

I'am using Google Cartographer package on ROS 2 Foxy for SLAM in a autonomous golf cart. When I do the rqt_graph of the system nodes and topics, I can see only the cartographer node publising in /tf topic, but, it doesn't subscribe to get the transforms. The SLAM is good, but, after a few time running the package, it stops mapping. I'm think this happens because the node isn't subscribed in transforms node.

This is my launch file:

import os
from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument
from launch_ros.actions import Node
from launch.substitutions import LaunchConfiguration
from launch.actions import IncludeLaunchDescription
from launch.launch_description_sources import PythonLaunchDescriptionSource
from launch.substitutions import ThisLaunchFileDir


def generate_launch_description():
    use_sim_time = LaunchConfiguration('use_sim_time', default='true')
    golfinho_cartographer_prefix = get_package_share_directory('golfinho_cartographer')
    cartographer_config_dir = LaunchConfiguration('cartographer_config_dir', default=os.path.join(
                                                  golfinho_cartographer_prefix, 'config'))
    configuration_basename = LaunchConfiguration('configuration_basename',
                                                 default='golfinho_2d.lua')

    resolution = LaunchConfiguration('resolution', default='0.2')
    publish_period_sec = LaunchConfiguration('publish_period_sec', default='1.0')

    rviz_config_dir = os.path.join(get_package_share_directory('golfinho_cartographer'),
                                   'rviz', 'golfinho_cartographer.rviz')

    return LaunchDescription([
        DeclareLaunchArgument(
            'cartographer_config_dir',
            default_value=cartographer_config_dir,
            description='Full path to config file to load'),
        DeclareLaunchArgument(
            'configuration_basename',
            default_value=configuration_basename,
            description='Name of lua file for cartographer'),
        DeclareLaunchArgument(
            'use_sim_time',
            default_value='true',
            description='Use simulation (Gazebo) clock if true'),

        Node(
            package='cartographer_ros',
            executable='cartographer_node',
            name='cartographer_node',
            output='screen',
            remappings=[
            ("/scan_1", "/golfinho/laser_front/out"), # Remapping laser topic to /scan
            ("/scan_2", "/golfinho/laser_left/out"), # Remapping laser topic to /scan_1
            ("/scan_3", "/golfinho/laser_right/out"), # Remapping laser topic to /scan_2
            ("/scan_4", "/golfinho/laser_back/out"), # Remapping laser topic to /scan_3
            ("/odom", "/golfinho/odom"),
            ("/imu", "/golfinho/imu_plugin_gazebo/out") 
            ],
            parameters=[{'use_sim_time': use_sim_time}],
            arguments=['-configuration_directory', cartographer_config_dir,
                       '-configuration_basename', configuration_basename]),

        DeclareLaunchArgument(
            'resolution',
            default_value=resolution,
            description='Resolution of a grid cell in the published occupancy grid'),

        DeclareLaunchArgument(
            'publish_period_sec',
            default_value=publish_period_sec,
            description='OccupancyGrid publishing period'),

        IncludeLaunchDescription(
            PythonLaunchDescriptionSource([ThisLaunchFileDir(), '/occupancy_grid.launch.py']),
            launch_arguments={'use_sim_time': use_sim_time, 'resolution': resolution,
                              'publish_period_sec': publish_period_sec}.items(),
        ),

        Node(
            package='rviz2',
            executable='rviz2',
            name='rviz2',
            arguments=['-d', rviz_config_dir],
            parameters=[{'use_sim_time': use_sim_time}],
            output='screen'),
    ])

And this my .lua config file:

include "map_builder.lua"
include "trajectory_builder.lua"

options = {
  map_builder = MAP_BUILDER,
  trajectory_builder = TRAJECTORY_BUILDER,
  map_frame = "map",
  tracking_frame = "imu_link",
  published_frame = "odom", --base_link
  odom_frame = "odom",
  provide_odom_frame = false,
  publish_frame_projected_to_2d = true,

  use_odometry = true,
  use_nav_sat = false,
  use_landmarks = false,
  num_laser_scans = 4,
  num_multi_echo_laser_scans = 0,
  num_subdivisions_per_laser_scan = 1,
  num_point_clouds = 0,
  lookup_transform_timeout_sec = 1.,
  submap_publish_period_sec = 0.3,
  pose_publish_period_sec = 5e-3,
  trajectory_publish_period_sec = 30e-3,
  rangefinder_sampling_ratio = 1.,
  odometry_sampling_ratio = 1.,
  fixed_frame_pose_sampling_ratio = 1.,
  imu_sampling_ratio = 1.,
  landmarks_sampling_ratio = 1.,
}

MAP_BUILDER.use_trajectory_builder_2d = true

TRAJECTORY_BUILDER_2D.min_range = 0.5
TRAJECTORY_BUILDER_2D.max_range = 300
TRAJECTORY_BUILDER_2D.missing_data_ray_length = 0
TRAJECTORY_BUILDER_2D.use_imu_data = true
TRAJECTORY_BUILDER_2D.use_online_correlative_scan_matching = true 
TRAJECTORY_BUILDER_2D.motion_filter.max_angle_radians = math.rad(0.1)

POSE_GRAPH.constraint_builder.min_score = 0.65
POSE_GRAPH.constraint_builder.global_localization_min_score = 0.7
POSE_GRAPH.optimize_every_n_nodes = 0

return options