Instructions

This SDK is only applicable to the LiDAR products sold by Shenzhen LDROBOT Co., LTD. The product models are :

• LDROBOT LiDAR LD14
• LDROBOT LiDAR LD14P

step 0: get LiDAR ROS Package

cd ~

mkdir -p ldlidar_ros_ws/src

cd ldlidar_ros_ws/src

git clone  https://github.com/ldrobotSensorTeam/ldlidar_sl_ros.git

step 1: system setup

• Connect the LiDAR to your system motherboard via an onboard serial port or usB-to-serial module (for example, CP2102 module).

• Set the -x permission for the serial port device mounted by the radar in the system (for example, /dev/ttyUSB0)

  • In actual use, the LiDAR can be set according to the actual mounted status of your system, you can use 'ls -l /dev' command to view.

cd ~/ldlidar_ros_ws

sudo chmod 777 /dev/ttyUSB0

• Modify the port_name value in the Lanuch file corresponding to the radar product model under launch/, using ld14.launch as an example, as shown below.

<?xml version="1.0"?>
<launch>
<arg name="laser_scan_topic_name" default="scan"/>
<arg name="point_cloud_2d_topic_name" default="pointcloud2d"/>
<arg name="frame_id" default="base_laser"/>
<arg name="port_name" default="/dev/ttyUSB0"/>
<arg name="fix_to_base_link" default="true" />

<!-- LDROBOT LiDAR message publisher node -->
 <node name="ldlidar_publisher_ld14" pkg="ldlidar_sl_ros" type="ldlidar_sl_ros_node" output="screen">
  <param name="product_name" value="LDLiDAR_LD14"/>
  <param name="laser_scan_topic_name" value="$(arg laser_scan_topic_name)"/>
  <param name="point_cloud_2d_topic_name" value="$(arg point_cloud_2d_topic_name)"/>
  <param name="frame_id" value="$(arg frame_id)"/>
  <param name="port_name" value="$(arg port_name)"/>
  <param name="serial_baudrate" value="115200"/>
  <!-- Set laser scan directon: -->
  <!--    1. Set counterclockwise, example: <param name="laser_scan_dir" type="bool" value="true"/> -->
  <!--    2. Set clockwise,        example: <param name="laser_scan_dir" type="bool" value="false"/> -->
  <param name="laser_scan_dir" type="bool" value="true"/>
  <!-- Angle crop setting, Mask data within the set angle range -->
  <!--    1. Enable angle crop fuction: -->
  <!--       1.1. enable angle crop,  example: <param name="enable_angle_crop_func" type="bool" value="true"/> -->
  <!--       1.2. disable angle crop, example: <param name="enable_angle_crop_func" type="bool" value="false"/> -->
  <param name="enable_angle_crop_func" type="bool" value="false"/>
  <!--    2. Angle cropping interval setting, The distance and intensity data within the set angle range will be set to 0 --> 
  <!--       angle >= "angle_crop_min" and angle <= "angle_crop_max", unit is degress -->
  <param name="angle_crop_min" type="double" value="135.0"/>
  <param name="angle_crop_max" type="double" value="225.0"/>
 </node>
 <!-- LDROBOT LiDAR message subscriber node -->
 <!-- node name="ldlidar_listener_ld14" pkg="ldlidar_sl_ros" type="ldlidar_sl_ros_listen_node" output="screen">
  <param name="topic_name" value="scan"/>
 </node -->
 <!-- publisher tf transform, parents frame is base_link, child frame is base_laser -->
 <!-- args="x y z yaw pitch roll parents_frame_id child_frame_id period_in_ms"-->
 <node name="base_to_laserLD14" pkg="tf" type="static_transform_publisher"  args="0.0 0.0 0.18 0 0.0 0.0 base_link base_laser 50" if="$(arg fix_to_base_link)"/>
</launch>

step 2: build

• install package depend

cd ~/ldlidar_ros_ws

rosdep install --from-paths src --ignore-src  -r -y

• build compile

cd ~/ldlidar_ros_ws

catkin_make

step 3: run

step3.1: package environment variable settings

• After the compilation is completed, you need to add the relevant files generated by the compilation to the environment variables, so that the ROS environment can recognize them. The execution command is as follows. This command is to temporarily add environment variables to the terminal, which means that if you reopen a new terminal, you also need to re-execute it. The following command.

  cd ~/ldlidar_ros_ws
  
  source devel/setup.bash

• In order to never need to execute the above command to add environment variables after reopening the terminal, you can do the following.

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

step3.2: start LiDAR node

• The product is LDROBOT LiDAR LD14
  • start ld14 lidar node:

  roslaunch ldlidar_sl_ros ld14.launch

  • start ld14 lidar node and show on the Rviz:

  # if ROS_DISTRO in 'kinetic' or 'melodic'
  roslaunch ldlidar_sl_ros viewer_ld14_kinetic_melodic.launch
  # if ROS_DISTRO in 'noetic'
  roslaunch ldlidar_sl_ros viewer_ld14_noetic.launch

• The product is LDROBOT LiDAR LD14P
  • start ld14p lidar node:

  roslaunch ldlidar_sl_ros ld14p.launch

  • start ld14p lidar node and show on the Rviz:

  # if ROS_DISTRO in 'kinetic' or 'melodic'
  roslaunch ldlidar_sl_ros viewer_ld14p_kinetic_melodic.launch
  # if ROS_DISTRO in 'noetic'
  roslaunch ldlidar_sl_ros viewer_ld14p_noetic.launch

step 4: test

The code was tested under ubuntu16.04 ROS kinetic、ubuntu18.04 ROS melodic、ubuntu20.04 ROS noetic, using rviz visualization.

• new a terminal (Ctrl + Alt + T) and use Rviz tool,open the rviz config file below the rviz folder of the readme file directory

rviz