[ros-users] About tf and synchronization

[Wim Meeussen]

> The problem is that I always get an error message like this:
>
> "You requested a transform that is 12.571 miliseconds in the past,
> but the most recent transform in the tf buffer is 49.194 miliseconds old.
>  When trying to transform between /swissranger and /map."

> I have already tried with "waitForTransform" between the two frames,
> but nothing seems to happen. I can see by using "rosrun tf
> view_frames" that amcl is publishing things in the future: "
> Broadcaster: /amcl ... Most recent transform: -0.086 sec old ... ".

Based on this information your tf tree looks fine. You are just
requesting a transformation before that information is in the tf
buffer.  Calling waitForTransform before you request the actual
transform should work.  Did you call waitForTransform with the same
frame id's and timestamp as the actual transform? Could you show the
few lines of code where you do the tf calls?

Wim


-- 
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Wim Meeussen
Willow Garage Inc.
<http://www.willowgarage.com)