LiDAR Service Interface

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LiDAR Data Acquisition Interface

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C++ Interface

Livox LiDAR (e.g., MID-360)

Overview

The LiDAR device supports access via the Livox SDK2 C++ API, which enables configuration of LiDAR IP and operating modes, retrieval of point cloud data, and access to built-in IMU data.

The SDK includes source code and precompiled dynamic/static libraries for integration.

Functionality	C++ Support	API Function
Configure LiDAR IP	✔	SetLivoxLidarIp
Set LiDAR Work Mode	✔	SetLivoxLidarWorkMode
Get Point Cloud Data	✔	SetLivoxLidarPointCloudCallBack
Get IMU Data	✔	SetLivoxLidarImuDataCallback

livox_status SetLivoxLidarIp(uint32_t handle, LivoxLidarIpInfo* ip_config, LivoxLidarAsyncControlCallback cb, void* client_data)

Description
Set LiDAR IP info.

Parameters

Parameter Name	Type	Required/Default	Description
handle	uint32_t	Required	Device handle.
ip_config	LivoxLidarIpInfo*	Required	Pointer to LiDAR IP config.
cb	LivoxLidarAsyncControlCallback	Required	Callback for result.
client_data	void*	Optional	User data.

Return Value

Type	Description
livox_status	kStatusSuccess on success.

livox_status SetLivoxLidarWorkMode(uint32_t handle, LivoxLidarWorkMode work_mode, LivoxLidarAsyncControlCallback cb, void* client_data)

Description
Set LiDAR work mode.

Parameters

Parameter Name	Type	Required/Default	Description
handle	uint32_t	Required	Device handle.
work_mode	LivoxLidarWorkMode	Required	Desired LiDAR work mode.
cb	LivoxLidarAsyncControlCallback	Required	Callback for result.
client_data	void*	Optional	User data.

Return Value

Type	Description
livox_status	kStatusSuccess on success.

void SetLivoxLidarPointCloudCallBack(LivoxLidarPointCloudCallBack cb, void* client_data)

Description
Register callback to receive point cloud data.

Parameters

Parameter Name	Type	Required/Default	Description
cb	LivoxLidarPointCloudCallBack	Required	Point cloud callback function.
client_data	void*	Optional	User data.

Return Value

Type	Description
void	No return value.

void SetLivoxLidarImuDataCallback(LivoxLidarImuDataCallback cb, void* client_data)

Description
Register callback to receive IMU data.

Parameters

Parameter Name	Type	Required/Default	Description
cb	LivoxLidarImuDataCallback	Required	IMU data callback function.
client_data	void*	Optional	User data.

Return Value

Type	Description
void	No return value.

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Usage Example

SetLivoxLidarPointCloudCallBack(PointCloudCallback, nullptr);

void PointCloudCallback(uint32_t handle, const uint8_t dev_type,
                        LivoxLidarEthernetPacket* data, void* client_data) {
  if (data == nullptr) return;

  printf("point cloud handle: %u, data_num: %d, data_type: %d, length: %d, frame_counter: %d\n",
         handle, data->dot_num, data->data_type, data->length, data->frame_cnt);

  if (data->data_type == kLivoxLidarCartesianCoordinateHighData) {
    auto* p_point_data = (LivoxLidarCartesianHighRawPoint*)data->data;
    for (uint32_t i = 0; i < data->dot_num; i++) {
      // Process p_point_data[i].x, y, z
    }
  } else if (data->data_type == kLivoxLidarCartesianCoordinateLowData) {
    auto* p_point_data = (LivoxLidarCartesianLowRawPoint*)data->data;
  } else if (data->data_type == kLivoxLidarSphericalCoordinateData) {
    auto* p_point_data = (LivoxLidarSpherPoint*)data->data;
  }
}

⚠Note

Each callback does not represent a complete LiDAR frame. You must aggregate at least 100 callbacks to form a full scan.

ROS 2 Interface

Overview

The LiDAR ROS 2 interface provides access to point cloud data via the /livox/lidar topic, using the sensor_msgs/msg/PointCloud2 message type. This includes raw 3D point data captured by the solid-state LiDAR.

Topic Information

Topic Name	Message Type	Role
/livox/lidar	sensor_msgs/msg/PointCloud2	Subscriber

Message Structure

std_msgs/Header header          # Message header containing timestamp and coordinate frame information
uint32 height                   # Height of the point cloud (usually 1 for unorganized clouds)
uint32 width                    # Width of the point cloud (number of points)
sensor_msgs/PointField[] fields # Definition of each point's fields (e.g., x, y, z, intensity, etc.)
bool is_bigendian               # Byte order of the data (usually false for little-endian)
uint32 point_step               # Number of bytes per point
uint32 row_step                 # Number of bytes per row
uint8[] data                    # Actual point cloud data in binary format
bool is_dense                   # Indicates whether the point cloud is dense (i.e., contains no invalid points)

Field Descriptions

Field Name	Type	Description
header	std_msgs/Header	Contains stamp (timestamp) and frame_id (coordinate frame).
height	uint32	Height of the point cloud (usually 1 for unorganized clouds).
width	uint32	Width of the point cloud (number of points per row or total number of points).
fields	sensor_msgs/PointField[]	Definition of each point's fields (e.g., x, y, z, intensity, etc.).
is_bigendian	bool	Byte order of the data (usually false for little-endian).
point_step	uint32	Number of bytes per point.
row_step	uint32	Number of bytes per row.
data	uint8[]	Actual point cloud data in binary format.
is_dense	bool	Indicates whether the point cloud is dense (i.e., contains no invalid points).

Callback Example

void lidarCallback(sensor_msgs::msg::PointCloud2::SharedPtr lidar_msg) {
    pcl::PointCloud<pcl::PointXYZI>::Ptr pc_pcl(new pcl::PointCloud<pcl::PointXYZI>());
    pcl::fromROSMsg<pcl::PointXYZI>(*lidar_msg, *pc_pcl);
    for (const auto& pc : pc_pcl->points) {
        /* <Customed processing procedure > */
    }
}

Testing Method

• Subscribe to LIDAR Message Data:

  For IS Robot (Livox)

ros2 topic echo /nav/livox/lidar_192_168_144_101

ros2 topic echo /nav/livox/lidar_192_168_144_102

For GS Robot (Robosense)

ros2 topic echo /nav/rslidar_points

Precautions

• Ensure the LiDAR driver node is correctly launched and actively publishing the corresponding topic before subscribing.
• Confirm the correct IP configuration and frame ID alignment if using multiple LiDAR units.