I am seeing your tf tree as this: /map -> /odom -> /base_link.  Which is ok, but you do not have a laser link so the laser data is not being transformed.  The laser data's frame is laser, but you don't have a joint between the base_link and the laser link, this causes it to not be viewable in rviz or be used by gmapping.  You need to define the geometric relationship between the position of the laser sensor and the base of the robot (/base_link -> /laser).

I would recommend reading this bit of the wiki: http://www.ros.org/wiki/tf/FAQ#Can_I_declare_static_transforms.3F

Hope that helps,

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Woodall
Graduate Software Engineering
Auburn University
w@auburn.edu
wjwwood@gmail.com
256-345-9938
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


On Thu, Jul 22, 2010 at 10:34 AM, Rishi Bedi <rbedi100@gmail.com> wrote:
David - I'm running Ubuntu 10.04, ROS 1.1.13-12 (installed through
synaptic), revision 107 of p2os (modified 2010-07-13).
Full SVN info output for p2os:

Path: .
URL: https://usc-ros-pkg.svn.sourceforge.net/svnroot/usc-ros-pkg/trunk/p2os
Repository Root: https://usc-ros-pkg.svn.sourceforge.net/svnroot/usc-ros-pkg
Repository UUID: 157d20ef-4c6e-4bb2-9484-52dd339cd29c
Revision: 107
Node Kind: directory
Schedule: normal
Last Changed Author: dfseifer
Last Changed Rev: 106
Last Changed Date: 2010-07-13 17:11:49 -0400 (Tue, 13 Jul 2010)

Here is the bagfile that I just recorded: www.rbedi.net/2010-07-22-11-29-38.bag

William - I didn't set anything up for my transforms -- I just set ROS
to record the /tf topic -- is there any setting up I need to do?

Thanks for all your help,
Rishi


On Thu, Jul 22, 2010 at 1:53 AM, David Feil-Seifer
<david.feilseifer@gmail.com> wrote:
> We at USC have been using P2OS concurrently with gmapping for months
> now, so I know that it CAN work. Let me help you debug this problem in
> more detail. Can you do me a favor and send me a link to that bag file
> that you recorded? Also, can you fill me in on what OS, ros release
> and version of the p2os stack (preferably the output of svn info from
> the p2os stack directory). That will help me figure this out in more
> detail.
>
> On Wed, Jul 21, 2010 at 10:02 PM, William Woodall <wjwwood@gmail.com> wrote:
>> I can't think of any reason why gmapping could not run concurrently with the
>> p2os driver.  All that the gmapping slam node needs is published laser scans
>> and correct TF data.  I have not used the p2os, but I would think it gives
>> this information already, if the gmapping system isn't working correctly
>> then I would look at the laser topic and the transforms to make sure that
>> they are publishing the correct data.  Specifically make sure your
>> transforms are setup correctly.  Judging from your error: "...TF_OLD_DATA
>> ignoring data from the past for frame /base_link at time..." I would say
>> that there is something wrong with the transformations you have setup.
>> Hope that helps,
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> William Woodall
>> Graduate Software Engineering
>> Auburn University
>> w@auburn.edu
>> wjwwood@gmail.com
>> 256-345-9938
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>>
>> On Wed, Jul 21, 2010 at 10:41 PM, nitinDhiman <nitinkdhiman@gmail.com>
>> wrote:
>>>
>>> Hi Rishi,
>>> Then does that mean we cannot do concurrent mapping with currently ROS
>>> packages. For pioneer, I heavily relying on p2os drivers.
>>>
>>> Has any one tried concurrent localisation and mapping? May be using some
>>> other setup??
>>>
>>> Thank you,
>>> Nitin
>>> --
>>> View this message in context:
>>> http://ros-users.122217.n3.nabble.com/gmapping-errors-tp981480p986050.html
>>> Sent from the ROS-Users mailing list archive at Nabble.com.
>>>
>>>
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