点云地图制作

LIO-SAM-6AXIS

lio-sam-6axis

prerequest

Ubuntu 22.04
ROS2 Humble

step-1: 构建建图工作空间

创建工作空间

mkdir ~/mapping_ws
cd ~/mapping_ws
mkdir src
cd src

step-2 clone仓库

git clone https://github.com/pixmoving-moveit/LIO-SAM-ROS2-PIXKIT # clone 仓库代码

step-3 安装依赖

sudo apt install ros-humble-perception-pcl \
       ros-humble-pcl-msgs \
       ros-humble-vision-opencv \
       ros-humble-xacro
# Add GTSAM-PPA
sudo add-apt-repository ppa:borglab/gtsam-release-4.1
sudo apt install libgtsam-dev libgtsam-unstable-dev

step-4 编译package

cd ~/mapping_ws
colcon build --symlink-install --cmake-args -DCMAKE_BUILD_TYPE=Release

step-5 标定传感器

在建图之前，需要准备好你的IMU的内参，还有LiDAR与IMU的外参

step-6 修改配置文件

launch文件

import os
from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument
from launch.substitutions import LaunchConfiguration, Command
from launch_ros.actions import Node


def generate_launch_description():

    share_dir = get_package_share_directory('lio_sam')
    parameter_file = LaunchConfiguration('params_file')
    xacro_path = os.path.join(share_dir, 'config', 'robot.urdf.xacro')
    rviz_config_file = os.path.join(share_dir, 'config', 'rviz2.rviz')

    params_declare = DeclareLaunchArgument(
        'params_file',
        default_value=os.path.join(
            share_dir, 'config', 'params_rs16.yaml'),
        description='FPath to the ROS2 parameters file to use.')

    print("urdf_file_name : {}".format(xacro_path))

    return LaunchDescription([
        params_declare,
        Node(
            package='tf2_ros',
            executable='static_transform_publisher',
            arguments='0.0 0.0 0.0 0.0 0.0 0.0 map odom'.split(' '),
            parameters=[parameter_file],
            output='screen'
            ),
        Node(
            package='robot_state_publisher',
            executable='robot_state_publisher',
            name='robot_state_publisher',
            output='screen',
            parameters=[{
                'robot_description': Command(['xacro', ' ', xacro_path])
            }]
        ),
        Node(
            package='lio_sam',
            executable='lio_sam_imuPreintegration',
            name='lio_sam_imuPreintegration',
            parameters=[parameter_file],
            output='screen'
        ),
        Node(
            package='lio_sam',
            executable='lio_sam_imageProjection',
            name='lio_sam_imageProjection',
            parameters=[parameter_file],
            output='screen'
        ),
        Node(
            package='lio_sam',
            executable='lio_sam_featureExtraction',
            name='lio_sam_featureExtraction',
            parameters=[parameter_file],
            output='screen'
        ),
        Node(
            package='lio_sam',
            executable='lio_sam_mapOptimization',
            name='lio_sam_mapOptimization',
            parameters=[parameter_file],
            output='screen'
        ),
        Node(
            package='lio_sam',
            executable='lio_sam_simpleGpsOdom',
            name='lio_sam_simpleGpsOdom',
            parameters=[parameter_file],
            output='screen'
        ),
        Node(
            package='rviz2',
            executable='rviz2',
            name='rviz2',
            arguments=['-d', rviz_config_file],
            output='screen'
        )
    ])

需要根据launch文件修改对应的参数文件，以上述的launch文件为例，使用的参数文件是params_rs16.yaml，所以应该在这个文件中修改相关参数

需要修改为你的传感器配置的msg

参数	msg 类型	描述
pointCloudTopic	sensor_msgs/Pointcloud2	LiDAR点云的topic
imuTopic	sensor_msgs/Imu	IMU的topic
odomTopic	nav_msgs/Odometry	IMU里程计topic，不需要修改
gpsTopic	nav_msgs/NavSatFix	gnss的定位topic

如果使用GNSS进行方位初始化，需要将useImuHeadingInitialization设为true
LiDAR参数

参数	描述
sensor	LiDAR的类型，可选`velodyne`, `ouster`, `livox`, `robosense`
N_SCAN	点云通道数，16线激光雷达即为16
Horizon_SCAN	LiDAR的横向分辨率，(Velodyne:1800, Ouster:512,1024,2048, Livox Horizon: 4000)
downsampleRate	下采样率，让N_SCAN/downsampleRate=16
lidarMinRange	最小点云距离，默认为1.5
lidarMaxRange	最大点云距离，默认为1000.0

IMU内参，参考IMU标定获取IMU内参

IMU intrinsics

参数	描述
imuAccNoise	3轴加速度计白噪声均值 (m/s^s)
imuGyrNoise	3轴陀螺白噪声均值 (rad/s)
imuAccBiasN	3轴加速度计零偏均值 (m/s^s)
imuGyrBiasN	3轴陀螺零偏均值 (rad/s)
imuGravity	当地重力加速度 (m/s^2)
imuRPYWeight	角度权重，默认0.01

IMU外参，参考LiDAR与IMU外参标定

IMU外参，可以使用[LiDAR与IMU外参标定]，也可以使用卷尺手动量取(坐标系为右手法则) 当手动量取时： - extrinsicTrans:卷尺手动量取 - extrinsicRot: 单位矩阵即可

IMU extrinsics

参数	描述
extrinsicTrans	平移矩阵
extrinsicRot	旋转矩阵

step-8: 运行建图程序

运行建图launch文件

ros2 launch lio_sam run.launch.py

播放rosbag

ros2 bag play --clock -r 3.0 -s sqlite3 [your_ros2_bag]

step-7: 保存地图

ros2 service call /lio_sam/save_map  lio_sam/srv/SaveMap "{resolution: 0.2, destination: [Absolute path to store your map]}"

保存好地图之后能够在地图文件夹内看到以下文件

name	描述
GlobalMap.pcd	点云地图，如果使用GNSS的话方向已经转换至ENU方向

你能够看到点云地图的原点WGS84坐标，用于GNSS定位 map-origin

建议把终端里的信息保存下来，方便用于GNSS定位时使用