[ros-users] Tf failure while working with a Pioneer P3DX

[Wim Meeussen]

Did you check if the clocks of the robot computer and your laptop are
synchronized?

Wim


On Wed, Dec 1, 2010 at 5:11 PM, devpriya <devpriya211084 at gmail.com> wrote:
>
> Hi Guys,
>
> The setup is like this, I have a MobileRobots PeopleBot. I wrote a
> playerstage wrapper for ROS so that ROS running on my laptop can communicate
> with the player server on the robot. The connection is through a wired
> ethernet.
>
> I am seeing a strange case of tf failure here. The transform from base_link
> to base_laser fails unless I subtract 1.75 seconds from the timestamp of
> laser transforms!
>
> I can see that the messages from odometery and laser scan are coming at
> almost the same rate. Even the timestamps are almost identical and I am
> timestamping these messages on the laptop.
>
> The workaround of subtracting 1.75 seconds from the laser timestamp fixes
> the base_link to base_laser transform but now when I try to run the
> 2dnavigation stack, the transform from map to base_laser won't happen
> because the messages are too old. Even increasing the tolerance to something
> like 2 seconds doesn't help as the buffer gets filled with old messages!
>
> I guess my hack of subtracting 1.75 seconds at the first place was a wrong
> move and I want to know if anybody had faced any such problem and if yes
> then how did you debug it?
>
> I have tried all the debugging techniques mentioned in the tf tutotrial on
> ROS's website. Everything looks fine in view_frames or roswtf.
>
> One more piece of information which might be helpful is that I am running
> Ubuntu on VmWare on MacBook Pro. I don't know if virtual machine has
> something to do in this, may be timing issue!
>
> If you need any more info to help me out, please let me know and I will
> furnish the same.
> --
> View this message in context: http://ros-users.122217.n3.nabble.com/Tf-failure-while-working-with-a-Pioneer-P3DX-tp2003281p2003281.html
> Sent from the ROS-Users mailing list archive at Nabble.com.
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-- 
--
Wim Meeussen
Willow Garage Inc.
<http://www.willowgarage.com)