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TF error in topological roadmap [closed]

asked 2012-03-27 06:03:16 -0500

prince gravatar image

I am running topological navigation (Revision: 54057) on ROS Diamondback. On launching move_base_topo_stage.launch in topological_roadmap package, a lot of TF errors similar to following appears:

[ERROR] [1332863239.641246114, 733.000000000]: Lookup would require extrapolation into the past.  Requested time 732.100000000 but the earliest data is at time 733.000000000, when looking up transform from frame [/grid6] to frame [/grid42]
[ERROR] [1332863239.955981566, 733.000000000]: TF Exception that should never happen for sensor frame: , cloud frame: base_laser_link, Lookup would require extrapolation into the past.  Requested time 732.200000000 but the earliest data is at time 733.000000000, when looking up transform from frame [/base_laser_link] to frame [/grid42]
[ERROR] [1332863239.956976386, 733.000000000]: TF Exception that should never happen for sensor frame: , cloud frame: base_laser_link, Lookup would require extrapolation into the past.  Requested time 732.300000000 but the earliest data is at time 733.000000000, when looking up transform from frame [/base_laser_link] to frame [/grid42]
[ERROR] [1332863239.957876360, 733.000000000]: TF Exception that should never happen for sensor frame: , cloud frame: base_laser_link, Lookup would require extrapolation into the past.  Requested time 732.400000000 but the earliest data is at time 733.000000000, when looking up transform from frame [/base_laser_link] to frame [/grid42]
[ERROR] [1332863239.958767605, 733.000000000]: TF Exception that should never happen for sensor frame: , cloud frame: base_laser_link, Lookup would require extrapolation into the past.  Requested time 732.500000000 but the earliest data is at time 733.000000000, when looking up transform from frame [/base_laser_link] to frame [/grid42]
[ERROR] [1332863239.969647689, 733.100000000]: TF Exception that should never happen for sensor frame: , cloud frame: base_laser_link, Lookup would require extrapolation into the past.  Requested time 732.600000000 but the earliest data is at time 733.000000000, when looking up transform from frame [/base_laser_link] to frame [/grid42]

what could be the cause of these? What could be solution? Or I can just ignore them (hoping that rejection of grid points will not change the map much!)

Thank you prince

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Closed for the following reason question is not relevant or outdated by tfoote
close date 2012-08-25 15:37:02

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Hmm, do these errors continue throughout the run, or do they only occur near the beginning?

bhaskara gravatar image bhaskara  ( 2012-03-29 05:43:58 -0500 )edit

If they appear, these continue throughout the run. Currently I am not able to localize why these do not occur everytime on execution? Sometimes these errors are not reported reported.

prince gravatar image prince  ( 2012-03-29 06:58:57 -0500 )edit

OK, please file this as a ticket at https://code.ros.org/trac/wg-ros-pkg.

bhaskara gravatar image bhaskara  ( 2012-03-29 07:44:44 -0500 )edit

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answered 2012-03-27 10:29:15 -0500

tfoote gravatar image

You should check that all your computers are accurately time synchronized with ntp, and if so file a bug with topological_navigation.

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All code is running on desktop in simulation environment (stage)! so i believe synchronization is not a problem.

prince gravatar image prince  ( 2012-03-27 23:32:52 -0500 )edit

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Asked: 2012-03-27 06:03:16 -0500

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Last updated: Mar 27 '12