LiDAR Data Communication Example

Livox-ros-driver2 Driver Installation Tutorial

Install Livox_ros_driver2 Package

Choose a location for the workspace (home directory as example). Open a terminal in the home directory and enter:

git clone https://github.com/Livox-SDK/livox_ros_driver2.git ws_livox/src/livox_ros_driver2

Explanation: Clone the livox_ros_driver2 package at the terminal location, creating a new workspace ws_livox, and install it in the src directory of workspace ws_livox.

Install Livox-SDK2 Package

Install cmake (skip if already installed)

sudo apt install cmake

Clone Livox-SDK2 Package

Open a terminal in the src directory of ws_livox and execute:

git clone https://github.com/Livox-SDK/Livox-SDK2.git

Now the livox_ros_driver2 package and Livox-SDK2 package are in the same directory.

Build Compilation Environment

cd ./Livox-SDK2/
mkdir build
cd build
cmake .. && make -j

Execute Installation Command

sudo make install

Livox-SDK2 installation is now complete.

Load Environment Configuration

Open a New Terminal

Configure ROS Environment

Using ROS1 (melodic) as an example:

source /opt/ros/melodic/setup.sh
./build.sh ROS1

Installation Verification

Load Livox Workspace Environment Variables

source ~/ws_livox/devel/setup.bash

Permanently Configure Livox Workspace Environment Variables (Optional)

echo "source ~/ws_livox/devel/setup.bash" >> ~/.bashrc

Refresh Terminal Environment Configuration

source ~/.bashrc

Search for Package Path

rospack find livox_ros_driver2

If the package path is output, ROS has recognized the Livox-ros-driver2 driver package.

Reference: GitHub - Livox-SDK/livox_ros_driver2

LiDAR Topic Description

X30 LiDAR topics are as follows:

Topic Name	Description	Message Type	Frequency
/livox/lidar	Livox LiDAR custom format point cloud data	livox_ros_driver2/CustomMsg	10Hz
/lidar_points	Generic format point cloud data	sensor_msgs/PointCloud2	10Hz

The message type livox_ros_driver2/CustomMsg for topic /livox/lidar is a custom message type:

std_msgs/Header header
  uint32 seq
  time stamp
  string frame_id
uint64 timebase
uint32 point_num
uint8 lidar_id
uint8[3] rsvd
livox_ros_driver2/CustomPoint[] points
  uint32 offset_time
  float32 x
  float32 y
  float32 z
  uint8 reflectivity
  uint8 tag
  uint8 line

To use rostopic echo on the robot dog terminal to view this topic, run:

source ~/jy_cog/drivers/setup.bash

To use rostopic echo on the local terminal to view this topic, you need to complete the Livox-ros-driver2 driver package installation first.

If developers need to subscribe to this topic in their own programs, they need to define the custom message structure in their program.

LiDAR Data Subscription Example Code

The following example demonstrates how to subscribe to the /livox/lidar topic and parse point cloud data:

#include "ros/ros.h"
#include "livox_ros_driver2/CustomMsg.h"

int g_count = 0;

void lidarCallback(const livox_ros_driver2::CustomMsg::ConstPtr& msg)
{
    g_count++;

    ROS_WARN("\n===== cycle：%d  =====", g_count);

    ROS_WARN("header: ");
    ROS_WARN("  seq: %u", msg->header.seq);
    ROS_WARN("  stamp: ");
    ROS_WARN("    secs: %u", msg->header.stamp.sec);
    ROS_WARN("    nsecs: %u", msg->header.stamp.nsec);
    ROS_WARN("  frame_id: \"%s\"", msg->header.frame_id.c_str());

    ROS_WARN("timebase: %lu", msg->timebase);
    ROS_WARN("point_num: %u", msg->point_num);
    ROS_WARN("lidar_id: %hhu", msg->lidar_id);
    ROS_WARN("rsvd: [%hhu, %hhu, %hhu]", msg->rsvd[0], msg->rsvd[1], msg->rsvd[2]);

    ROS_INFO("points: ");
    for (size_t i = 0; i < msg->points.size(); ++i) {
        const auto& point = msg->points[i];
        ROS_INFO("  - ");
        ROS_INFO("    offset_time: %u", point.offset_time);
        ROS_INFO("    x: %f, y: %f, z: %f", point.x, point.y, point.z);
        ROS_INFO("    reflectivity: %hhu, tag: %hhu, line: %hhu",
                 point.reflectivity, point.tag, point.line);
    }
    ROS_WARN("---");
}

int main(int argc, char **argv)
{
    ros::init(argc, argv, "lidar_subscriber");
    ros::NodeHandle nh;

    ros::Subscriber sub = nh.subscribe("/livox/lidar", 1000, lidarCallback);
    ros::spin();

    return 0;
}

CMakeLists.txt Configuration

find_package(catkin REQUIRED COMPONENTS
  geometry_msgs
  roscpp
  rospy
  std_msgs
  message_generation
  livox_ros_driver2
)

add_message_files(FILES CustomMsg.msg)
generate_messages(DEPENDENCIES std_msgs livox_ros_driver2)

catkin_package(
  CATKIN_DEPENDS roscpp rospy std_msgs message_runtime livox_ros_driver2
)

add_executable(lidar_subscriber src/lidar_subscriber.cpp)
target_link_libraries(lidar_subscriber ${catkin_LIBRARIES})
add_dependencies(lidar_subscriber ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

package.xml Configuration

<build_depend>message_generation</build_depend>
<exec_depend>message_runtime</exec_depend>
<build_depend>livox_ros_driver2</build_depend>
<exec_depend>livox_ros_driver2</exec_depend>

Run

source devel/setup.bash
rosrun livox_custom lidar_subscriber