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Hello everyone I am using ROS 2 Eloquent (Ubuntu 18.04) and am currently studying Nav2. I wanted to try the work of slam_toolbox together with the lidar of RPLIDAR S1. To do this, I run:

ros2 launch rplidar_ros2 view_rplidar_s1_launch.py

And then I launch:

ros2 launch slam_toolbox online_async_launch.py

I expected to get /map output, however I see an error:

[slam_toolbox-1] [INFO] [slam_toolbox]: Message Filter dropping message: frame 'laser' at time 1646404216.077 for reason 'Unknown'

After reading the documentation and package description, I realized that slam_toolbox requires TF transforms from odom->base link. However, I don't quite understand how to get the right /tf, has anyone encountered this? I will be glad of any help!

Originally posted by Dr.Modi on ROS Answers with karma: 7 on 2022-03-04

Post score: 0


1 Answer 1


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The Nav 2 Transformations and odometry documentation are pretty helpful:



You need something to publish the odometry transform you’re missing. It’s confusing because there are many possible sources for that transform and it depends on how you setup your robot. Here are some examples:

  • A motor controller driver that publishes wheel odometry based on wheel encoders
  • A gazebo plug-in in a simulated robot
  • A tracking camera driver such as the RealSense T265
  • the ros2_control framework
  • The robot_localization package that can fuse multiple odometry sources such as wheel encoders, IMU, or GPS
  • and more….

Originally posted by dognaught47 with karma: 91 on 2022-03-08

This answer was ACCEPTED on the original site

Post score: 1


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