[ros-users] Interfacing a new arm driver to a motion planner

Sun Dec 5 22:01:48 UTC 2010

Hi Antons,
I have looked into your configs and it look very similar to mine.
But I still have a problem with ompl which don't respect collisions and plan
trajectories through obstacles.
Did you had similar problems ?

Pozdrawiam
Konrad Banachowicz

2010/12/5 Antons Rebguns <anton at email.arizona.edu>

> Hi folks,
>
> I just went through all the same stuff as both of you to get the arm
> navigation pipeline work on our custom 7DOF dynamixel based arm. I was able
> to use the ompl motion planning stack to generate a collision free
> trajectory that was successfully executed in both simulation and the the
> actual arm. I would say if you can reliably execute a joint trajectory on
> you arm it's a relatively small step to get the planning environment set up
> so that you can get ompl running.
>
> Here's what I had to write to get it going:
>
> 1). arm_kinematics - your basic IK solver. Provides the following services:
>   a). get_ik
>   b). get_fk
>    c). get_ik_solver_info
>   d). get_fk_solver_info
>
> Packages:
>   PR2: pr2_arm_kinematics
>   Mine:
> http://code.google.com/p/ua-ros-pkg/source/browse/#svn/trunk/arrg/ua_controllers/wubble_arm_kinematics
>
> 2). arm_kinematics_constraint_aware - basically a wrapper around
> arm_kinematics. Hooks up to planning environment and checks the initial and
> desired poses for collisions, also publishes some visualization markers.
> Adds get_constraint_aware_ik service to all those provided by
> arm_kinematics.
>
> Packages:
>   PR2: pr2_arm_kinematics_constraint_aware
>   Mine:
> http://code.google.com/p/ua-ros-pkg/source/browse/#svn/trunk/arrg/ua_controllers/wubble_arm_kinematics_constraint_aware
>
> 3). joint_trajectory_action_controller - does what you think it does. If
> your are already does that, I think all you'd need to do is write a wrapper
> that creates a ROS action interface to it.
>
> Packages:
>   PR2: robot_mechansim_controllers - joint_trajectory_action_controller.cpp
>   Mine:
> http://code.google.com/p/ua-ros-pkg/source/browse/#svn/trunk/arrg/ua_controllers/ax12_controller_core/nodes
>
> 4). After that you would need to write a bunch of yaml configuration files:
>   a). parameters for motion planning
>   b). parameters for collision checks and self filtering
>   c). for collision map - collision sources, basically something that
> provides a point cloud of stuff around you, like a tilting laser.
>   d). for collision map - self filter, stuff that should not be present in
> the cloud above.
>   e). some padding parameters for planning_environment
>   f). parameters for ompl_planning and ompl_search
>
>     PR2: pr2_arm_navigation stack has all those scattered across a bunch of
> packages.
>
>   You could look at my launch file, it is pretty long but it that has
> everything in one place:
>
> http://code.google.com/p/ua-ros-pkg/source/browse/trunk/arrg/ua_robots/wubble_description/launch/wubble2_empty_world.launch
>
> All the parameters that it loads are in here (w2_*.yaml):
>
> http://code.google.com/p/ua-ros-pkg/source/browse/#svn/trunk/arrg/ua_robots/wubble_description/params
>
> So I think you guys are pretty close to get the motion planner run on your
> arms, at least the motion planning part, now the grasping pipeline is whole
> different matter... I don't have experience with that, yet :)
>
> Hope this helps you somewhat,
> Anton
>
> On Sun, Dec 5, 2010 at 10:59 AM, Konrad Banachowicz <konradb3 at gmail.com>wrote:
>
>> Hi Martin,
>>
>> I am doing quiet the same for irb6 manipulator. I have done all servo,
>> trajectory, URDF stuff already.
>> Now i am working on running manipulation pipeline on it. For now it's
>> looks like it would be hard work.
>> The manipulation pipeline (as far as i know) is used only on PR2 and It's
>> quiet hard to get any answers about it on the list.
>> I recently get some stuff working (envirement_server, move_arm,
>> trajectory_filter) (partially by some ugly hacks) but there is still a lot
>> of work before I can say it works for me.
>>
>> Pozdrawiam
>> Konrad Banachowicz
>>
>>
>> 2010/12/5 Martin Günther <martin.guenther1980 at googlemail.com>
>>
>> On Sun, 5 Dec 2010 17:39:30 +0100
>>> Martin Günther <mguenthe at uos.de> wrote:
>>>
>>> > Dear list,
>>> >
>>> > I am currently writing a ROS node for the Neuronics Katana 450 arm and
>>> > would be happy about a few quick pointers about how to continue. I am
>>> > aware of the ROS packages katana450, katana_ik_bridge and
>>> > stair_katana; however, I would like to reuse as much ROS stuff for
>>> > IK, arm navigation and motion planning as possible, so I decided to
>>> > rewrite the code from scratch.
>>> >
>>> > So far,
>>> > - I have created a URDF description of the arm;
>>> > - I can read out the current joint angles and publish them as
>>> > JointState messages;
>>> > - I can move the arm to a desired joint angle configuration;
>>> > - I can move the arm to a target pose in space, using the inverse
>>> >   kinematics library supplied with the arm (although I'm also eager to
>>> >   give the ROS IK a try).
>>> >
>>> > I have the feeling that I am almost done (right? come on, please!),
>>> > but I'm a little overwhelmed by the wealth of arm navigation stuff in
>>> > ROS. What are the messages/services/actions that I should provide to
>>> > be able to interface my arm to a motion planner, and to use the ROS
>>> > IK, and so on?
>>> >
>>> > Best,
>>> > Martin
>>>
>>> Forgot to mention: The robot arm has realtime controllers for all the
>>> motors; I can send a spline (or a sequence of splines) there, and it
>>> will be executed.
>>>
>>> Best,
>>> Martin
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>>
>>
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