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Frozen map + 'Message filter dropping'... Issues with mapping and navigation

asked 2021-04-25 11:53:44 -0600

jacobwaller gravatar image

Hello everyone, sorry for the long post, just want to make sure i include all the details.

I am working on learning ROS2 by building a robot which maps and navigates my apartment.

  • I'm using the RPLidar A1 sensor with the RPLidar package

  • a Robot Create 2 as the chassis with the create_robot package

  • nav2 for navigation

  • slam-toolbox for mapping

and running everything off of a Raspberry Pi 4 4GB with Ubuntu Mate

Currently, I am able to get LIDAR readings to successfully be viewed in RVIZ. I can also get one or two frames of a map to be built. When the robot starts to move, the lidar readings update, but the map itself does not. However, i continue to 'receive' map updates at about 1 every 1.5 seconds.

Here are images from rviz showing the moving scan but with the non-moving map:

I'm also getting a few errors, from RVIZ i am getting: [rviz]: Message Filter dropping message: frame 'map' at time 1619194935.882 for reason 'Unknown'

from nav2, I am getting [global_costmap.global_costmap_rclcpp_node]: Message Filter dropping message: frame 'laser' at time 1619194959.629 for reason 'Unknown'

My frame map looks like this (Most of the frames are created by the create_robotpackage):

I suspect my issue is with my transforms, either they're configured completely wrong, or there is something small

  • slam_toolbox does the transform from map -> odom
  • the create_robot package has other transforms from base_link to wheels, bumpers, etc and it also publishes odom data
  • using tf2, i'm publishing a transform between base_link and laser and then laser to base_scan.
  • I am also creating a transform from odom to base_footprint because of a ros2 navigation course i was taking on the construct.

Has anyone seen this type of error before? I feel like I am most of the way to the solution but i'm missing something easy

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Hi there, Having the very same issues. Any luck in solving them?

Per Edwardsson gravatar image Per Edwardsson  ( 2021-09-28 08:39:26 -0600 )edit

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answered 2021-10-19 21:11:57 -0600

tonaaskarwur gravatar image

From the image and error, I think your problem is in the odom. The parent and child frame ids looks neat in the tf frames. The message filter drop error shows that theres something missing in the timing. Did you set up the timestamp on the odom publisher? Do you have a odom time wall? Theres an odom sanity check that you could probably try out. For the error from nav2, not really sure but check your tf static (laser to base link) if its set up properly. If your robot receives only the initial map (in rviz) but doesnt update as you move the robot, then the problem must be in the odom.

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Asked: 2021-04-25 11:53:44 -0600

Seen: 663 times

Last updated: Oct 19 '21