slam_toolbox + LD19 LIDAR

Question

I recently purchased the LIDAR LD19. I managed to configure it and it is working fine, presenting the data in the RVIZ (LaserScan).

The LIDAR node is configured as described at: https://github.com/Myzhar/ldrobot-lidar-ros2/. Below I have a photo of the LIDAR LD19 presenting the Laserscan on the Rviz.

My question is: I would like to make a SLAM process and for that I am using the slam_toolbox framework (ROS2 Humble). I set up slam_toolbox following a tutorial and apparently managed to subscribe to the /ldlidar_node/scan thread. As shown in the image below.

To configure slam_toolbox I used the yaml file described at: https://github.com/SteveMacenski/slam_toolbox/blob/ros2/launch/online_async_launch.py

I opened RVIZ2, activated the map. I added the map topic, but I can't generate the map (SLAM) at all. The funny thing is that apparently ldlidar_node is being processed by slam_toolbox (you can see in the terminal that it is subscribed to the topic). But the map is not generated.

Could you let me know if LD-19 Lidar is compatible with ROS2 slam_toolbox? Is there any other framework, compatible, that I can generate the SLAM?

Answer 1

I haven't used the slam_toolbox recently but it is probably something with your TF-Tree. You can see the tree in rqt and then open the tf tree plugin under visualization, I think.

There should be an odom link with an arrow to base_link. If not you haven't configured your odometry correctly. I think you can also configure the slam_toolbox to publish the map to base_link transform directly. But this is not recommended. See REP 105.

Just searching for the message in your terminal:

• [slam_toolbox]: Message Filter dropping message: for reason 'discarding message because the queue is full'
• Slam Toolbox: Message Filter dropping message for reason 'discarding message because the queue is full'
• Slam_toolbox "discarding message because the queue is full" on a Jetson Xavier.