Dear Ruben,
Are you using KDL::TreeIkSolverPos_NR_JL for the inverse position
kinematics ? If it is the case, would you have an example? I can't find
any on the web :S
Cheers,
Ugo
On 07/04/10 12:08, Ruben Smits wrote:
> On Wednesday 07 April 2010 12:48:23 Sachin Chitta wrote:
>
>> Hi Ugo,
>>
>> You can use KDL to do inverse kinematics using one of the inverse
>> kinematics solvers in the package. These are numerical solvers that
>> operate on a KDL chain. First use the kdl_parser package to create a KDL
>> chain and then initialize an inverse kinematics solver for the chain. The
>> solution tends to be dependent on the initial state you pass into the
>> solver and can sometimes get stuck in local minima. Also, I am not sure
>> about how well the solvers handle joint limits. I believe more advanced
>> solvers are in the works but I will let the orocos folks comment on that.
>>
>
> If you need inverse velocity kinematics, which is commonly the case in
> a control application, KDL contains various implementations including
> the use of (task and/or robot space weighted)pseudo-inverses of the
> jacobian and (damped) least squares solutions of the inverse velocity
> problem. More advanced (constraint-based) solvers are currently being
> developed, but these are still at the velocity level.
>
>
> If you need inverse position kinematics, KDL does currently not have a
> perfect solution, at the moment we only have an implementation of a
> Newton-Raphson integration on top of one of the inverse velocity
> kinematic solvers.
>
> Ruben
>
>
>> Have a look at the api page here
>> http://orocos.org/kdl/UserManual/kinematic_solvers for more examples.
>>
> This page (sadly) does not cover all the existing solvers :(
>
>
>> The other option is to write your own solver (we have one for the PR2 that
>> takes in a hint for one of the joint angles and then computes the other 6
>> analytically -
>> www.ros.org/wiki/pr2_arm_kinematics<http://www.ros.org/wiki/pr2_arm_kinema
>> tics>)
>>
>> Sachin
>>
>> On Wed, Apr 7, 2010 at 3:28 AM, Ugo Cupcic
>> <ugo@shadowrobot.com<mailto:ugo@shadowrobot.com>> wrote: Hi all,
>>
>> Is it possible to use robot_state_publisher or some other ROS stack to
>> do reverse kinematic on my urdf model?
>> Or do I need to implement my own using the "Coding a realtime Cartesian
>> controller with KDL" tutorial ?
>>
>> Cheers,
>>
>> Ugo
>>
>>
>> --
>> Ugo Cupcic | Shadow Robot Company |
>> ugo@shadowrobot.com<mailto:ugo@shadowrobot.com> Software Engineer 251
>> Liverpool Road
>> need a Hand? London N1 1LX | +44 20 7700 2487
>> http://www.shadowrobot.com/hand/ @shadowrobot
>>
>> _______________________________________________
>> ros-users mailing list
>> ros-users@code.ros.org<mailto:ros-users@code.ros.org>
>> https://code.ros.org/mailman/listinfo/ros-users
>>
>>
>>
>> --
>> Sachin Chitta
>> Research Scientist
>> Willow Garage
>>
> _______________________________________________
> ros-users mailing list
> ros-users@code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users
>
>
--
Ugo Cupcic | Shadow Robot Company | ugo@shadowrobot.com
Software Engineer 251 Liverpool Road
need a Hand? London N1 1LX | +44 20 7700 2487
http://www.shadowrobot.com/hand/ @shadowrobot
(text/plain)