After reviewing the tutorials, you can start by building the urdf, e.g. make
a copy of pr2_description/robots/pr2.urdf.xacro, and strip out anything
other than the base, e.g.

<?xml version="1.0"?>
<robot xmlns:sensor="
http://playerstage.sourceforge.net/gazebo/xmlschema/#sensor"
       xmlns:controller="
http://playerstage.sourceforge.net/gazebo/xmlschema/#controller"
       xmlns:interface="
http://playerstage.sourceforge.net/gazebo/xmlschema/#interface"
       xmlns:xacro="
http://playerstage.sourceforge.net/gazebo/xmlschema/#interface"
       name="pr2" >

  <!-- The following included files set up definitions of parts of the robot
body -->
  <!-- misc common stuff? -->
  <include filename="$(find pr2_description)/urdf/common.xacro" />
  <!-- PR2 base -->
  <include filename="$(find pr2_description)/urdf/base_v0/base.urdf.xacro"
/>
  <!-- generic simulator_gazebo plugins for starting mechanism control, ros
time, ros battery -->
  <include filename="$(find pr2_description)/gazebo/gazebo.urdf.xacro" />

  <!-- materials for visualization -->
  <include filename="$(find pr2_description)/urdf/materials.urdf.xacro" />

  <!-- Now we can start using the macros included above to define the actual
PR2 -->

  <!-- The first use of a macro.  This one was defined in base.urdf.xacro
above.
       A macro like this will expand to a set of link and joint definitions,
and to additional
       Gazebo-related extensions (sensor plugins, etc).  The macro takes an
argument, name,
       that equals "base", and uses it to generate names for its component
links and joints
       (e.g., base_link).  The included origin block is also an argument to
the macro.  By convention,
       the origin block defines where the component is w.r.t its parent (in
this case the parent
       is the world frame). For more, see http://www.ros.org/wiki/xacro -->
  <xacro:pr2_base_v0 name="base"/>

</robot>

Then you probably want to mimic pr2_gazebo/pr2.launch to bring up the above
urdf xacro and remove any ros node that is not PR2 base-specific.
hope this helps,
John

On Wed, Aug 4, 2010 at 4:19 PM, Tully Foote <tfoote@willowgarage.com> wrote:

> Also, If you do want to jump right in the package
> http://www.ros.org/wiki/pr2_gazebo has a launch file loading a model with
> no arms.  But I still suggest that you do the tutorials first.
>
> Tully
>
>
> On Wed, Aug 4, 2010 at 4:17 PM, Tully Foote <tfoote@willowgarage.com>wrote:
>
>> Hi Sam,
>>
>> I would suggest that you try out the existing tutorials for stage and or
>> gazebo http://www.ros.org/wiki/simulator_stage/Tutorials   and
>> http://www.ros.org/wiki/simulator_gazebo/Tutorials  and from there you
>> should have an idea of how to use simulation.
>>
>> What you want to do in using a partial robot, is equivalent to making and
>> configuring your own robot and although completely doable,
>> (The fundamentals are explained in one of the above linked tutorials)  the
>> complications required will hamper your learning of the rest of the systems.
>>
>>
>> Tully
>>
>>
>> On Tue, Aug 3, 2010 at 11:16 PM, Sam Quintanar <robosq@hotmail.com>wrote:
>>
>>>  I'd like to start using the PR2 simulation.
>>> I've already done the PR2 installation and gone through the first 18 of
>>> the beginners_tutorials and completed the questionnaire at the end.
>>>
>>> My first goal is to play with "only" the "omnidirectional base" of the
>>> PR2 to get a good feel of how the simulation works and what it takes to run
>>> the omnidirectional base software-wise.
>>> *1- What must I do to see "only" the base operate in simulation?*
>>>
>>> My second goal is to purchase the hardware for the omnidirectional base
>>> and see it actually work.
>>>
>>> *2- Is my first goal feasible, and if so, what are the steps I need to
>>> take toward my goal?*
>>> Please point me to where I need to start concerning using and customizing
>>> the simulation.
>>>
>>> Thanks..........and BTW....THIS IS A FANTASTIC USERSLIST!! THE BEST I'VE
>>> EVER ENCOUNTERED!
>>>
>>> SamQ
>>>
>>> _______________________________________________
>>> ros-users mailing list
>>> ros-users@code.ros.org
>>> https://code.ros.org/mailman/listinfo/ros-users
>>>
>>>
>>
>>
>> --
>> Tully Foote
>> Systems Engineer
>> Willow Garage, Inc.
>> tfoote@willowgarage.com
>> (650) 475-2827
>>
>
>
>
> --
> Tully Foote
> Systems Engineer
> Willow Garage, Inc.
> tfoote@willowgarage.com
> (650) 475-2827
>
> _______________________________________________
> ros-users mailing list
> ros-users@code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users
>
>