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move_base changes clock of mapping node

asked 2013-11-22 04:28:13 -0500

pkohout gravatar image

updated 2013-12-12 20:13:39 -0500

tfoote gravatar image

Hi, i am using stage to simulate two robots. Mapping runs, but if i start move_base for the first roboter, its tf stops working. So i researched a little bit and found out that if i start move_base for robot_0 the map frame is published with a total different time. On the left (robot_0) with move_base started, on the right (robot_1) without move_base.

Why is the Most recent transform changing?

image description

And now move_base throws the following warning:

[ WARN] [1385137274.474605959]: Waiting on transform from /robot_0/base_footprint to /robot_0/map to become available before running costmap, tf error: Unable to lookup transform, cache is empty, when looking up transform from frame [/robot_0/base_footprint] to frame [/robot_0/map]

The tf tree is correct, so i take a look at the move_base source and the error is thrown in costmap_2d_ros.cpp:165

I have tried setting use_sim_time to true and to false, but the result always keep the same. And i used gmapping and hector_mapping, get the same problem by both

Anyone an idea how to solve that?

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if you need more information, just tell me

pkohout gravatar image pkohout  ( 2013-11-22 04:28:31 -0500 )edit

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answered 2013-12-12 20:15:36 -0500

tfoote gravatar image

With that large of a jump it is most likely that one of your robots is starting up using simulated time and the other is using Wall time. Make sure that you have set the using_sim_time before either of your robots has started.

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I forgot to set the using_sim_time parameter to true, now it works

pkohout gravatar image pkohout  ( 2013-12-15 19:42:25 -0500 )edit

Great. Please accept the answer by clicking the checkmark at the left of the answer so others know the question is answered without reading your comment.

tfoote gravatar image tfoote  ( 2013-12-15 19:44:44 -0500 )edit

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Asked: 2013-11-22 04:28:13 -0500

Seen: 176 times

Last updated: Dec 12 '13