建图的过程

1、修改配置

参数文件：src/cartographer_ros/cartographer_ros/configuration_files/revo_lds.lua；
其中修改的地方有：
tracking_frame = "laser",
published_frame = "laser",
use_odometry = false

include "map_builder.lua" 
include "trajectory_builder.lua" options = {
  map_builder = MAP_BUILDER,
  trajectory_builder = TRAJECTORY_BUILDER,
  map_frame = "map",
  tracking_frame = "laser",  
  published_frame = "laser",  
  odom_frame = "odom",
  provide_odom_frame = true,
  publish_frame_projected_to_2d = false,
  use_pose_extrapolator = true,
  use_odometry = false,
  use_nav_sat = false,
  use_landmarks = false,
  num_laser_scans = 1,
  num_multi_echo_laser_scans = 0,
  num_subdivisions_per_laser_scan = 1,
  num_point_clouds = 0,
  lookup_transform_timeout_sec = 0.2,
  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.submaps.num_range_data = 35 TRAJECTORY_BUILDER_2D.min_range = 0.3 TRAJECTORY_BUILDER_2D.max_range = 8.
TRAJECTORY_BUILDER_2D.missing_data_ray_length = 1.
TRAJECTORY_BUILDER_2D.use_imu_data = false TRAJECTORY_BUILDER_2D.use_online_correlative_scan_matching = true TRAJECTORY_BUILDER_2D.real_time_correlative_scan_matcher.linear_search_window = 0.1 TRAJECTORY_BUILDER_2D.real_time_correlative_scan_matcher.translation_delta_cost_weight = 10.
TRAJECTORY_BUILDER_2D.real_time_correlative_scan_matcher.rotation_delta_cost_weight = 1e-1 POSE_GRAPH.optimization_problem.huber_scale = 1e2
POSE_GRAPH.optimize_every_n_nodes = 35 POSE_GRAPH.constraint_builder.min_score = 0.65 return options

2、注意：修改完配置文件，需要重新编译；

catkin_make -DCATKIN_WHITELIST_PACKAGES=cartographer_ros

3、启动文件：

src/cartographer_ros/cartographer_ros/launch/rplidar_demo_revo_lds.launch；
这里要修改的是
<param name="/use_sim_time" value="true" /> ，
<remap from="scan" to="scan" />

<launch>
  <param name="/use_sim_time" value="true" />

  <node name="cartographer_node" pkg="cartographer_ros" type="cartographer_node" args="
          -configuration_directory $(find cartographer_ros)/configuration_files -configuration_basename revo_lds.lua"
      output="screen">
    <remap from="scan" to="scan" />
  </node>

  <node name="rviz" pkg="rviz" type="rviz" required="true" args="-d $(find cartographer_ros)/configuration_files/demo_2d.rviz" />  

</launch>