3D-SLAM入门教程-多线雷达(RSlidar 16)loam_velodyne 3D建图

ROS与SLAM入门教程-多线雷达(RSlidar 16)loam_velodyne 3D建图

说明：

• 介绍如何使用多线雷达(RSlidar 16)结合loam_velodyne算法进行三维建图
• 测试环境：turbot-DL + 多线雷达RSlidar 16

loam_velodyne

• loam_velodyne是Loam的velodyne雷达版本，Loam(Laser Odometry and Mapping)是使用3D激光雷达进行状态估计和建图的实时方法。 该程序包含两个并行运行的主线程。 “odometry”线程以更高的帧速率计算激光雷达在两次扫描之间的运动。 它还消除了激光雷达运动引起的点云失真。 “Mapping”线程采用未失真的点云并逐步构建地图，同时以较低的帧速率计算地图上激光雷达的姿势。 激光雷达状态估计是来自两个线程的输出的组合。

• 我们目前使用多线雷达，所以需要对loam_velodyne改善。

loam_velodyne准备

• 录制ros包，参考：https://www.ncnynl.com/archives/201810/2759.html

• 安装loam_velodyne

cd ~/rslidar_ws/src
git clone https://github.com/laboshinl/loam_velodyne.git
cd  ..
catkin_make

• 进入launch目录

roscd loam_velodyne/launch/

• 增加loam_rslidar.launch

<launch>

  <node pkg="tf" type="static_transform_publisher" name="rslidarlink_broadcaster" args="0.0 0.0 0.42 0.0 0.0 0.0 base_link laser 50"/>

  <arg name="rviz" default="false" />
  <arg name="scanPeriod" default="0.1" />
  <arg name="lidartype" default="VLP-16" /> <!-- options: VLP-16  HDL-32  HDL-64E RS-32 RS-16-->


  <node pkg="loam_velodyne" type="multiScanRegistration" name="multiScanRegistration" output="screen">
    <param name="lidar" value="$(arg lidartype)" /> <!-- options: VLP-16  HDL-32  HDL-64E RS-32 RS-16 -->
    <param name="scanPeriod" value="$(arg scanPeriod)" />

    <remap from="/multi_scan_points" to="/rslidar_points" />
    <remap from="/imu/data"  to="/mobile_base/sensors/imu_data" />
  </node>

  <node pkg="loam_velodyne" type="laserOdometry" name="laserOdometry" output="screen" respawn="true">
    <param name="scanPeriod" value="$(arg scanPeriod)" />
  </node>

  <node pkg="loam_velodyne" type="laserMapping" name="laserMapping" output="screen">
    <param name="scanPeriod" value="$(arg scanPeriod)" />
    <remap from="/imu/data"  to="/mobile_base/sensors/imu_data" />
  </node>

  <node pkg="loam_velodyne" type="transformMaintenance" name="transformMaintenance" output="screen">
  </node>

  <group if="$(arg rviz)">
    <node launch-prefix="nice" pkg="rviz" type="rviz" name="rviz" args="-d $(find loam_velodyne)/rviz_cfg/loam_velodyne.rviz" />
  </group>

</launch>

• 根据实际情况，设置雷达的TF，我们放在turtlebot2的顶托盘中心。

• 使用雷达的3D点云和turtlebot2小车的IMU数据

• 新件rslidar_rviz.launch

<launch>
  <node launch-prefix="nice" pkg="rviz" type="rviz" name="rviz" args="-d $(find loam_velodyne)/rviz_cfg/loam_velodyne.rviz" />
</launch>

loam_velodyne 离线建图

• 新终端，启动roscore

roscore

• 新终端，启动rslidar

roslaunch loam_velodyne loam_rslidar.launch

• 新终端，rosbag包回放

rosbag play 2018-10-16-17-45-53.bag

• 或者选择数据好的时间段

rosbag play -s 50 2018-10-16-17-45-53.bag

• 新终端，运行rviz

roslaunch loam_velodyne rslidar_rviz.launch

loam_velodyne 实时建图

• 新终端，启动底盘

roslaunch turtlebot_bringup minimal.launch

• 新终端，启动rslidar雷达

roslaunch rslidar_pointcloud rs_lidar_16.launch

• 新终端，启动键盘控制

roslaunch turtlebot_teleop keyboard_teleop.launch

• 新终端，启动loam_velodyne建图

roslaunch loam_velodyne loam_rslidar.launch

• 新终端，运行rviz

roslaunch loam_velodyne rslidar_rviz.launch