I am trying to get the cartographer to work on my platform running ubuntu18.04 and ROS melodic. I have modified the configuration file and urdf to accept a laser scan. The urdf and config file sis attached. For some reason, the cartographer_node crashes with an exit code -6. The terminal is as given below.

wh@wh--Y7000:~/catkin_ws$ roslaunch cartographer_ros demo_my_robot.launch bag_filename:=${HOME}/Downloads/out_2019-06-18-10-09-07.bag
... logging to /home/wh/.ros/log/943fa3f0-b5c4-11e9-8f21-8c1645e9392a/roslaunch-wh--Y7000-10103.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://wh--Y7000:41385/

SUMMARY
========

PARAMETERS
 * /robot_description: <...>
 * /rosdistro: melodic
 * /rosversion: 1.14.3
 * /use_sim_time: True

NODES
  /
    cartographer_node (cartographer_ros/cartographer_node)
    cartographer_occupancy_grid_node (cartographer_ros/cartographer_occupancy_grid_node)
    playbag (rosbag/play)
    robot_state_publisher (robot_state_publisher/robot_state_publisher)
    rviz (rviz/rviz)

auto-starting new master
process[master]: started with pid [10113]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to 943fa3f0-b5c4-11e9-8f21-8c1645e9392a
process[rosout-1]: started with pid [10124]
started core service [/rosout]
process[robot_state_publisher-2]: started with pid [10128]
process[cartographer_node-3]: started with pid [10132]
process[cartographer_occupancy_grid_node-4]: started with pid [10133]
process[rviz-5]: started with pid [10139]
process[playbag-6]: started with pid [10146]
[ INFO] [1564819152.334285584]: I0803 15:59:12.000000 10132 configuration_file_resolver.cc:41] Found '/home/wh/catkin_ws/install_isolated/share/cartographer_ros/configuration_files/my_robot3d.lua' for 'my_robot3d.lua'.
[ INFO] [1564819152.335315105]: I0803 15:59:12.000000 10132 configuration_file_resolver.cc:41] Found '/home/wh/catkin_ws/install_isolated/share/cartographer/configuration_files/map_builder.lua' for 'map_builder.lua'.
[ INFO] [1564819152.335358026]: I0803 15:59:12.000000 10132 configuration_file_resolver.cc:41] Found '/home/wh/catkin_ws/install_isolated/share/cartographer/configuration_files/map_builder.lua' for 'map_builder.lua'.
[ INFO] [1564819152.335468322]: I0803 15:59:12.000000 10132 configuration_file_resolver.cc:41] Found '/home/wh/catkin_ws/install_isolated/share/cartographer/configuration_files/pose_graph.lua' for 'pose_graph.lua'.
[ INFO] [1564819152.335512335]: I0803 15:59:12.000000 10132 configuration_file_resolver.cc:41] Found '/home/wh/catkin_ws/install_isolated/share/cartographer/configuration_files/pose_graph.lua' for 'pose_graph.lua'.
[ INFO] [1564819152.335634632]: I0803 15:59:12.000000 10132 configuration_file_resolver.cc:41] Found '/home/wh/catkin_ws/install_isolated/share/cartographer/configuration_files/trajectory_builder.lua' for 'trajectory_builder.lua'.
[ INFO] [1564819152.335687720]: I0803 15:59:12.000000 10132 configuration_file_resolver.cc:41] Found '/home/wh/catkin_ws/install_isolated/share/cartographer/configuration_files/trajectory_builder.lua' for 'trajectory_builder.lua'.
[ INFO] [1564819152.335770674]: I0803 15:59:12.000000 10132 configuration_file_resolver.cc:41] Found '/home/wh/catkin_ws/install_isolated/share/cartographer/configuration_files/trajectory_builder_2d.lua' for 'trajectory_builder_2d.lua'.
[ INFO] [1564819152.335837415]: I0803 15:59:12.000000 10132 configuration_file_resolver.cc:41] Found '/home/wh/catkin_ws/install_isolated/share/cartographer/configuration_files/trajectory_builder_2d.lua' for 'trajectory_builder_2d.lua'.
[ INFO] [1564819152.335965318]: I0803 15:59:12.000000 10132 configuration_file_resolver.cc:41] Found '/home/wh/catkin_ws/install_isolated/share/cartographer/configuration_files/trajectory_builder_3d.lua' for 'trajectory_builder_3d.lua'.
[ INFO] [1564819152.335999089]: I0803 15:59:12.000000 10132 configuration_file_resolver.cc:41] Found '/home/wh/catkin_ws/install_isolated/share/cartographer/configuration_files/trajectory_builder_3d.lua' for 'trajectory_builder_3d.lua'.
[ INFO] [1564819152.340214057]: I0803 15:59:12.000000 10132 submap_3d.cc:321] Added submap 1
[ INFO] [1564819152.340278976]: I0803 15:59:12.000000 10132 map_builder_bridge.cc:130] Added trajectory with ID '0'.
[ INFO] [1564819152.793690522, 1560823747.639238343]: I0803 15:59:12.000000 10132 ordered_multi_queue.cc:172] All sensor data for trajectory 0 is available starting at '636964205476402650'.
[ INFO] [1564819152.798626133, 1560823747.639238343]: I0803 15:59:12.000000 10132 local_trajectory_builder_3d.cc:78] Range data collator filling buffer.
[ INFO] [1564819152.817084031, 1560823747.659440112]: I0803 15:59:12.000000 10132 local_trajectory_builder_3d.cc:78] Range data collator filling buffer.
[ INFO] [1564819152.817798706, 1560823747.659440112]: I0803 15:59:12.000000 10132 local_trajectory_builder_3d.cc:96] Extrapolator is still initializing.
[ INFO] [1564819152.893957122, 1560823747.740068206]: I0803 15:59:12.000000 10132 local_trajectory_builder_3d.cc:96] Extrapolator is still initializing.
F0803 15:59:18.525882 10132 imu_tracker.cc:66] Check failed: (orientation_ * gravity_vector_).z() > 0. (0 vs. 0) 

**[FATAL] [1564819158.526156175, 1560823753.369341261]: F0803 15:59:18.000000 10132 imu_tracker.cc:66] Check failed: (orientation_ * gravity_vector_).z() > 0. (0 vs. 0)**
*** Check failure stack trace: ***
    @     0x7f5d9eb080cd  google::LogMessage::Fail()
    @     0x7f5d9eb09f33  google::LogMessage::SendToLog()
    @     0x7f5d9eb07c28  google::LogMessage::Flush()
    @     0x7f5d9eb0a999  google::LogMessageFatal::~LogMessageFatal()
    @     0x55f772257c59  (unknown)
    @     0x55f7721ff4e1  (unknown)
    @     0x55f77220055a  (unknown)
    @     0x55f7721af30a  (unknown)
    @     0x7f5d9c2d6a47  ros::TimerManager<>::TimerQueueCallback::call()
    @     0x7f5d9c30ae8c  ros::CallbackQueue::callOneCB()
    @     0x7f5d9c30c27b  ros::CallbackQueue::callAvailable()
    @     0x7f5d9c3642e9  ros::SingleThreadedSpinner::spin()
    @     0x7f5d9c34cb5b  ros::spin()
    @     0x55f7721a1146  (unknown)
    @     0x55f77219e164  (unknown)
    @     0x7f5d9ac98b97  __libc_start_main
    @     0x55f7721a0aaa  (unknown)

[cartographer_node-3] process has died [pid 10132, exit code -6, cmd /home/wh/catkin_ws/install_isolated/lib/cartographer_ros/cartographer_node -configuration_directory /home/wh/catkin_ws/install_isolated/share/cartographer_ros/configuration_files -configuration_basename my_robot3d.lua points2_1:=velodyne_points points2_2:=velodyne_points_1 points2_3:=velodyne_points_2 __name:=cartographer_node __log:=/home/wh/.ros/log/943fa3f0-b5c4-11e9-8f21-8c1645e9392a/cartographer_node-3.log].
log file: /home/wh/.ros/log/943fa3f0-b5c4-11e9-8f21-8c1645e9392a/cartographer_node-3*.log

cartographerrosbagvalidate my bag

and my .lua .lanuch .urdf in attachment