How to slam using YDLidar

[hyng809]

Hello
This is the first time using YDLidar.
I have verified that Lidar works through Rviz on Ubuntu.
I want to create maps and use navigation using Lidar, which I am currently using.
I would like to know more detailed process and tutorial about this.
This is the development environment I am currently developing.

• Ubuntu 20.04
• ROS2 foxy
  -YDLidar TG15
• Raspberry Pi 4
  -PC

[anasderkaoui]

• Make sure you install "slam_toolbox" (package to do SLAM): sudo apt update && sudo apt install ros-foxy-slam-toolbox
• Turn on the LiDAR: ros2 launch ydlidar_ros2_driver ydlidar_launch_view.py (This also launches the tf tree required for slam, but you have to change "base_link" in this line to "base_footprint" and rebuild the package)
• In another terminal, run: ros2 run tf2_ros static_transform_publisher 0 0 0 0 0 0 odom base_footprint Do this only if you don't have an odometry output from like wheel encoders...
• Now run in another terminal: ros2 launch slam_toolbox online_sync_launch.py This is just an example, there are other options, you can view them by double pressing the tab key. After that, you should see "Registering Sensor..."
• Finally, run RVIZ2 and add the topic "map", it takes a moment to load the map but it eventually shows up!!

[ndp-seee-hust]

Hello @anasderkaoui. Thank for sharing!
I have followed your instructions and I have a problem. My map cannot update or expand when I rotate and move the Lidar. Please help me fix this problem!

• YDLidar X3
• Ubuntu 20.04
• ROS2 foxy

[anasderkaoui]

Hello @ndp-seee-hust, make sure that you have the odometry node running.
This was, in my case, one of the main reasons the map did not update. And also, move the lidar very slowly and don't rotate it suddenly because that will overlap the maps that will be created.
I advise you to take a look at my repo for more detailed information.