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Help needed on understandinge ComputeIk

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Help needed on understandinge ComputeIk

Jeroen
Hi,
I am new to openrave and running into some things I do not understand.

We have a 6 DOF robotarm, which is our own design. We made an openrave model of it. Tested the Openrave (translation3D) inverse kinematics with python. That seems to work ok.

Then we generated the inverse kinmeatics module according to http://openrave.org/docs/latest_stable/openravepy/databases.inversekinematics/
and tested it. Also this seems to work.

Now I have trouble understanding how to use the generated cpp code.

In typical example code I find the expression:
    bool bSuccess = ComputeIk(eetrans, eerot, vfree.size() > 0 ? &vfree[0] : NULL, solutions);

However, I generated a 3D translation IK, so the rotation matrix should not be used, I assume.
Furthermore, I have trouble understanding the third parameter. I want the IK to use all joints required to get a certain translation. What should vfree be?

Hope you can help me out here.

Kind regards,
Jeroen
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Re: Help needed on understandinge ComputeIk

Praveen
Hi,

"Till you get reply."

As I understand, you want to use all the joints for a 3D translation IK but you need only three joints to solve the IK, right ?
Do you want multiple solutions ? or Do you want to find if a solution exists by changing the free indices ?

Best Regards
Praveen
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Re: Help needed on understandinge ComputeIk

Jeroen
Hi Praveen,

Yes, I want to use alle joints for a 3D translation. Then there will be multiple solutions, and I will pick one.
Kind regards,
Jeroen Veen

-----Oorspronkelijk bericht-----
Van: Praveen [mailto:[hidden email]]
Verzonden: maandag 9 december 2013 19:02
Aan: [hidden email]
Onderwerp: Re: [OpenRAVE-users] Help needed on understandinge ComputeIk

Hi,

"Till you get reply."

As I understand, you want to use all the joints for a 3D translation IK but you need only three joints to solve the IK, right ?
Do you want multiple solutions ? or Do you want to find if a solution exists by changing the free indices ?

Best Regards
Praveen



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Re: Help needed on understandinge ComputeIk

Praveen
Hi Jeroen,

I am not sure if there is inbuilt function which can do that for us but you can always create several 3D Ik with different free indices and iterate over each to get a solution and pick one. Is collision the only criteria that you want to consider choosing one of the multiple solutions ? If yes, then you have to generate a trajectory and compare if there is collision free path that exists.

Best Regards
Praveen
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