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Error: For frame [Laser]: Frame does not exist

asked 2019-06-03 11:22:19 -0500

vincent_m gravatar image

Hi!,

I am trying to build a map using roslaunch turtlebot3_slam turtlebot3_slam.launch slam_methods:=gmapping on a turtlebot3. Unfortunately I have issues with the LIDAR.

I wrote my own publisher following the tutorial Publishing Sensor Streams Over ROS, to see if gmapping works with "fake" data. However I am getting the error "Fixed Frame [laser] does not exist" both with this method and running roslaunch rplidar_ros rplidar.launch (I am using a RPLIDAR instead of the stock LIDAR coming with the turtlebot) . I cannot upload a file since I do not have enough points.

Thanks for any help

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I cannot upload a file since I do not have enough points.

what would you want to show us?

gvdhoorn gravatar imagegvdhoorn ( 2019-06-03 11:48:25 -0500 )edit

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answered 2019-06-03 11:41:18 -0500

gvdhoorn gravatar image

This error indicates that even though your LaserScan messages are being received (by "a" consumer, you don't tell us which), there are no TF transform broadcasts to backup the laser frame that has been specified as value for frame_id in your messages (in the Header).

You'll have to make sure that you either:

  1. use a static_transform_broadcaster to provide a transform between something and laser
  2. use a URDF with a link named laser to the scene with a joint
  3. make the laser frame the root of everything

if you already have a turtlebot URDF, I would suggest to use either option 1 or 2, preferably option 2.

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Thank you, your 2. suggestion worked!

vincent_m gravatar imagevincent_m ( 2019-06-10 09:16:43 -0500 )edit

I saw this in the previous response you posted:

Our consumer should be rviz, as we are trying to build in map there.

pedantic, but important: RViz is just a simulator. It does not do any mapping, nor is it involved in the process, other than letting you observe the progress that some other node(s) publish.

So although RViz is "a consumer" of the data, and it does need a correct TF tree, it only needs it to be able to visualise your sensor data for you.

gvdhoorn gravatar imagegvdhoorn ( 2019-06-11 02:05:01 -0500 )edit

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Asked: 2019-06-03 11:22:19 -0500

Seen: 315 times

Last updated: Jun 03