YDLIDAR ROS2 Driver

ydlidar_ros2_driver is a new ros package, which is designed to gradually become the standard driver package for ydlidar devices in the ros2 environment.

How to install ROS2

ubuntu

windows

How to Create a ROS2 workspace

Create a workspace

Compile & Install YDLidar SDK

ydlidar_ros2_driver depends on YDLidar-SDK library. If you have never installed YDLidar-SDK library or it is out of date, you must first install YDLidar-SDK library. If you have installed the latest version of YDLidar-SDK, skip this step and go to the next step.

1. Download or clone the YDLIDAR/YDLidar-SDK repository on GitHub.
2. Compile and install the YDLidar-SDK under the build directory following README.md of YDLIDAR/YDLidar-SDK.

Clone ydlidar_ros2_driver

1. Clone ydlidar_ros2_driver package for github :

   git clone https://github.com/YDLIDAR/ydlidar_ros2_driver.git ydlidar_ros2_ws/src/ydlidar_ros2_driver

2. Build ydlidar_ros2_driver package :

   cd ydlidar_ros2_ws
   colcon build --symlink-install
   

Note: install colcon see

1. Package environment setup :

   source ./install/setup.bash

   Note: Add permanent workspace environment variables. It’s convenientif the ROS2 environment variables are automatically added to your bash session every time a new shell is launched:

    $echo "source ~/ydlidar_ros2_ws/install/setup.bash" >> ~/.bashrc
    $source ~/.bashrc
    

1. Confirmation To confirm that your package path has been set, printenv the grep -i ROS variable.

    $ printenv | grep -i ROS
    

You should see something similar to:
    `OLDPWD=/home/tony/ydlidar_ros2_ws/install`

1. Create serial port Alias [optional]

	$chmod 0777 src/ydlidar_ros2_driver/startup/*
	$sudo sh src/ydlidar_ros2_driver/startup/initenv.sh
    

Note: After completing the previous operation, replug the LiDAR again.

Configure LiDAR paramters

ydlidar_ros2_driver_node:
  ros__parameters:
    port: /dev/ttyUSB0
    frame_id: laser_frame
    ignore_array: ""
    baudrate: 230400
    lidar_type: 1
    device_type: 0
    sample_rate: 9
    abnormal_check_count: 4
    resolution_fixed: true
    reversion: true
    inverted: true
    auto_reconnect: true
    isSingleChannel: false
    intensity: false
    support_motor_dtr: false
    angle_max: 180.0
    angle_min: -180.0
    range_max: 64.0
    range_min: 0.01
    frequency: 10.0
    invalid_range_is_inf: false

Run ydlidar_ros2_driver

Run ydlidar_ros2_driver using launch file

The command format is :

ros2 launch ydlidar_ros2_driver [launch file].py

1. Connect LiDAR uint(s).

   ros2 launch ydlidar_ros2_driver ydlidar_launch.py 
   

or

   launch $(ros2 pkg prefix ydlidar_ros2_driver)/share/ydlidar_ros2_driver/launch/ydlidar.py 
   

1. RVIZ

   ros2 launch ydlidar_ros2_driver ydlidar_launch_view.py 
   

![View](images/view.png  "View")

1. echo scan topic

   ros2 run ydlidar_ros2_driver ydlidar_ros2_driver_client or ros2 topic echo /scan
   

Launch file introduction

The driver offers users a wealth of options when using different launch file. The launch file directory

is "ydlidar_ros2_ws/src/ydlidar_ros2_driver/launch". All launch files are listed as below :

Publish Topic

| Topic | Type | Description | |———————-|————————-|————————————————–| | scan | sensor_msgs/LaserScan | 2D laser scan of the 0-angle ring |

Subscribe Service

| Service | Type | Description | |———————-|————————-|————————————————–| | stop_scan | std_srvs::Empty | turn off lidar | | start_scan | std_srvs::Empty | turn on lidar |

Configure ydlidar_ros_driver internal parameter

The ydlidar_ros2_driver internal parameters are in the launch file, they are listed as below :

| Parameter name | Data Type | detail | | ————– | ——- | ———————————————————— | | port | string | Set Lidar the serial port or IP address
it can be set to /dev/ttyUSB0, 192.168.1.11, etc.
default: /dev/ydlidar | | frame_id | string | Lidar TF coordinate system name.
default: laser_frame | | ignore_array | string | LiDAR filtering angle area
eg: -90, -80, 30, 40 | | baudrate | int | Lidar baudrate or network port.
default: 230400 | | lidar_type | int | Set lidar type
0 – TYPE_TOF
1 – TYPE_TRIANGLE
2 – TYPE_TOF_NET
default: 1 | | device_type | int | Set device type
0 – YDLIDAR_TYPE_SERIAL
1 – YDLIDAR_TYPE_TCP
2 – YDLIDAR_TYPE_UDP
default: 0 | | sample_rate | int | Set Lidar Sample Rate.
default: 9 | | abnormal_check_count | int | Set the number of abnormal startup data attempts.
default: 4 | | fixed_resolution | bool | Fixed angluar resolution.
default: true | | reversion | bool | Reversion LiDAR.
default: true | | inverted | bool | Inverted LiDAR.
false – ClockWise.
true – CounterClockWise
default: true | | auto_reconnect | bool | Automatically reconnect the LiDAR.
true – hot plug.
default: true | | isSingleChannel | bool | Whether LiDAR is a single-channel.
default: false | | intensity | bool | Whether LiDAR has intensity.
true – G2 LiDAR.
default: false | | support_motor_dtr | bool | Whether the Lidar can be started and stopped by Serial DTR.
default: false | | angle_min | float | Minimum Valid Angle.
default: -180 | | angle_max | float | Maximum Valid Angle.
default: 180 | | range_min | float | Minimum Valid range.
default: 0.1 | | range_max | float | Maximum Valid range.
default: 16.0 | | frequency | float | Set Scanning Frequency.
default: 10.0 | | invalid_range_is_inf | bool | Invalid Range is inf.
true – inf.
false – 0.0.
default: false | More paramters details, see here

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