've been playing with arm motion planning (OMPL) on a non-PR2 robot 
for a while now. I am currently working with a Schunk arm and a 
ShadowRobot hand at the tip. Both devices are controlled on different 
computers, and a custom made node fuses the joint information from both 
so that a single robot_description (and robot state) is obtainable. The 
problem I am having is that OMPL generates a collision-free plan, 
possibly even the Trajectory Filter, but during the execution move_arm 
stops crying for collisions that don&#39;t exist. The symptoms are: <ul><li>Right
 after a goal is requested, all of the nodes that use the 
motion_planning_common stack complain that &quot;Empty joint state map cache&quot;
 and &quot;Got joint state update but did not update some joints for more 
than 1 second.  Turn on DEBUG for more info&quot;</li><li>If I send a 
MoveArmAction request where disable_collision_monitoring is true, 
somebody (OMPL? TrajectoryFilter?) decides that there are not obstacles 
and plans a perfect straight line trajectory.</li></ul> <p>In the past I
 have successfully generated plans with a hand-less 7dof arm, now I 
don&#39;t understand what I am doing wrong! In particular, the warning 
messages I receive are really puzzling...</p><br clear="all"><br>-- <br>Lorenzo Riano, PhD<br>Research Associate<br>Intelligent Systems Research Centre<br>University of Ulster<br>Magee campus<br>Londonderry<br>BT48 7JL<br>
<br>phone: +44 (0)28 71375187<br>email: <a href="mailto:l.riano@ulster.ac.uk" target="_blank">l.riano@ulster.ac.uk</a>, <a href="mailto:lorenzo.riano@gmail.com" target="_blank">lorenzo.riano@gmail.com</a><br>skype: lorenzo.riano<br>
<br>Webpage: <a href="http://isrc.ulster.ac.uk/Staff/LRiano/Contact.html" target="_blank">http://isrc.ulster.ac.uk/Staff/LRiano/Contact.html</a><br>