ROS（10）turtlebot仿真（利用cartographer_ros）

10. turtlebot仿真（利用cartographer_ros替换karto）

参考链接
https://blog.youkuaiyun.com/qq_34935373/article/details/111991920
https://www.freesion.com/article/9794248452/

10.1. 官方纯定位Pure localization仿真测试

10.1.1. 下载数据集

wget -P mnt/e/wsl/cartographer_demo/pureLoc/ https://storage.googleapis.com/cartographer-public-data/bags/backpack_2d/b2-2016-04-05-14-44-52.bag  
wget -P mnt/e/wsl/cartographer_demo/pureLoc/ https://storage.googleapis.com/cartographer-public-data/bags/backpack_2d/b2-2016-04-27-12-31-41.bag

第一个用于建图，第二个用于定位。

10.1.2. 建图

自己的路径：

roslaunch cartographer_ros offline_backpack_2d.launch bag_filenames:=/mnt/e/wsl/cartographer_demo/pureLoc/b2-2016-04-05-14-44-52.bag

生成.pbstream的地图文件.

10.1.3. 定位

自己的路径：

roslaunch cartographer_ros demo_backpack_2d_localization.launch \
   load_state_filename:=/mnt/e/wsl/cartographer_demo/pureLoc/b2-2016-04-05-14-44-52.bag.pbstream \
   bag_filename:=/mnt/e/wsl/cartographer_demo/pureLoc/b2-2016-04-27-12-31-41.bag

这里第一个参数是用的地图，第二个参数是下载的数据集进行定位测试。

10.2. turtlebot3仿真建图

• 首先修改/opt/ros/melodic/share/turtlebot3_slam/config/turtlebot3_lds_2d.lua中的tracking_frame = "base_footprint"

• 然后执行：
  roslaunch turtlebot3_slam turtlebot3_slam.launch slam_methods:=cartographer

• 保存地图，参考https://google-cartographer-ros.readthedocs.io/en/latest/assets_writer.html:
  rosservice call /write_state /mnt/e/wsl/maps/carto.pbstream 1
rosrun map_server map_saver -f /mnt/e/wsl/maps/carto

写的地图数据可以通过assets_writer_backpack_3d.lua来进行配置。

• pbstream转pgm地图：
  rosrun cartographer_ros cartographer_pbstream_to_ros_map -map_filestem=${HOME}/Downloads/mymap -pbstream_filename=${HOME}/Downloads/mymap.pbstream -resolution=0.05

10.3. turtlebot3仿真导航

[关键]上个步骤中实际已经启动了move_base节点，可以一边扫图一边导航控制。具体可查看turtlebot3_cartographer.launch文件。

10.3.1. turtlebot3_cartographer.launch最终文件

在建图和导航时，分别注释掉相关部分即可。
建图和导航的指令均为：roslaunch turtlebot3_slam turtlebot3_slam.launch slam_methods:=cartographer

<launch>
  <!-- Arguments -->
  <arg name="model" default="$(env TURTLEBOT3_MODEL)" doc="model type [burger, waffle, waffle_pi]"/>
  <arg name="configuration_basename" default="turtlebot3_lds_2d.lua"/>
  <arg name="map_file" default="/mnt/e/wsl/maps/carto.yaml"/>
  <arg name="load_state_filename" default="/mnt/e/wsl/maps/carto.pbstream"/>

  <!-- move_base -->
  <include file="$(find turtlebot3_navigation)/launch/move_base.launch">
    <arg name="model" value="$(arg model)" />
  </include>

  <!-- cartographer_node 只有在建图的时候打开-->
  <node pkg="cartographer_ros" type="cartographer_node" name="cartographer_node" 
        args="-configuration_directory $(find turtlebot3_slam)/config
              -configuration_basename $(arg configuration_basename)"
        output="screen">
    <remap from="/imu" to="/flat_imu"/>
  </node>
  <!-- cartographer_occupancy_grid_node 只有在建图的时候打开-->
  <node pkg="cartographer_ros" type="cartographer_occupancy_grid_node"
        name="cartographer_occupancy_grid_node" 
        args="-resolution 0.05" />

  <!-- Map server 建图的时候屏蔽该节点，只在导航时候打开
  <node pkg="map_server" name="map_server" type="map_server" args="$(arg map_file)"/>-->
  <!-- cartographer_node 只在导航时候打开
  <node pkg="cartographer_ros" type="cartographer_node" name="cartographer_node" 
        args="-configuration_directory $(find turtlebot3_slam)/config
              -configuration_basename $(arg configuration_basename)
              -load_state_filename $(arg load_state_filename)"
        output="screen">
    <remap from="/imu" to="/flat_imu"/>
  </node>-->

  <!-- flat_world_imu_node -->
  <node pkg="turtlebot3_slam" type="flat_world_imu_node" name="flat_world_imu_node" output="screen">
    <remap from="imu_in" to="/imu" />
    <remap from="imu_out" to="/flat_imu" />
  </node>
</launch>

10.3.2. 建图或导航节点关系图