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Tilting Laser Problem : PR2 blocked by a virtual obstacle wall

asked 2013-09-27 03:23:50 -0500

Albert K
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updated 2013-09-29 21:19:55 -0500

When I run the pr2_2dnav_slam, the tilting laser seems to have some problem. Therefore the robot will think that it is stuck in the obstacles and won't move.

fig1

Then I try to show the tilting laser alone.

fig2

It looks like that there are some problem with the transform from the tilting laser to the base_link.

Beside, the laser seems to be wrapped up in a circle, which is very similar to the condition in fig1.

Is there any wrong with the setting of the tilting laser, or what might the problem be?

Thanks for any advise.

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answered 2013-09-28 21:17:42 -0500

tfoote

58457 ●128 ●550 ●526 http://www.ros.org/

I've seen this sort of errors when there's a timing offset between computers on the PR2. The tilting laser is very sensitive to timing offsets since it moves quickly.

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I checked the dashboard and found that there are warnings like "NTP offset from c1 to c2 ; Offset too great." Therefore I followed this: pr2support.willowgarage.com/wiki/PR2 Manual/Chapter13#Clock_Synchronization, and sync the clock. After that the problem disappeared!! Thank you very much~

Albert K ( 2013-09-29 21:24:24 -0500 )edit

I wonder why the tilting laser is sensitive to the timing offset? How does the timing offset interact with the system that finally result in such phenomenon.

Albert K ( 2013-09-29 21:26:37 -0500 )edit

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Asked: 2013-09-27 03:23:50 -0500

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Last updated: Sep 29 '13

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