Looking for CalculateRotationHessian()

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Looking for CalculateRotationHessian()

stephane-caron
Hi everybody,

I am transitioning from a velocity- to an acceleration-controlled
framework. Gladly, I found that all jacobian functions I had been using,
like ComputeJacobianAxisAngle() or ComputeJacobianTranslation(), had a
Hessian counterpart (resp. ComputeHessianAxisAngle() or
ComputeHessianTranslation()).

All jacobian functions? Alas, there is but one missing.
CalculateRotationJacobian(), which yields the quaternion representation
of the rotation, is still waiting for a CalculateRotationHessian()...

For the time being, I use a dirty:

    J = lambda q: robot.CalculateRotationJacobian(link, q)
    qd_H_qd = lambda q, qd: (dot(J(q + qd * 1e-5) - J(q), qd)) / 1e-5

Is there any prospect of a CalculateRotationHessian() coming to RAVE robots?

Best,

--
Stéphane Caron


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Re: Looking for CalculateRotationHessian()

Rosen Diankov
Administrator
hi stephane,

glad you are getting into such advanced functionality ;0)
if you can point us in the right direction to a quaterion version of the second order Jacobian, then i'd be glad to add it to openrave.

best,


2015-01-20 20:55 GMT+09:00 Stéphane Caron <[hidden email]>:
Hi everybody,

I am transitioning from a velocity- to an acceleration-controlled
framework. Gladly, I found that all jacobian functions I had been using,
like ComputeJacobianAxisAngle() or ComputeJacobianTranslation(), had a
Hessian counterpart (resp. ComputeHessianAxisAngle() or
ComputeHessianTranslation()).

All jacobian functions? Alas, there is but one missing.
CalculateRotationJacobian(), which yields the quaternion representation
of the rotation, is still waiting for a CalculateRotationHessian()...

For the time being, I use a dirty:

    J = lambda q: robot.CalculateRotationJacobian(link, q)
    qd_H_qd = lambda q, qd: (dot(J(q + qd * 1e-5) - J(q), qd)) / 1e-5

Is there any prospect of a CalculateRotationHessian() coming to RAVE robots?

Best,

--
Stéphane Caron


------------------------------------------------------------------------------
New Year. New Location. New Benefits. New Data Center in Ashburn, VA.
GigeNET is offering a free month of service with a new server in Ashburn.
Choose from 2 high performing configs, both with 100TB of bandwidth.
Higher redundancy.Lower latency.Increased capacity.Completely compliant.
http://p.sf.net/sfu/gigenet
_______________________________________________
Openrave-users mailing list
[hidden email]
https://lists.sourceforge.net/lists/listinfo/openrave-users



------------------------------------------------------------------------------
New Year. New Location. New Benefits. New Data Center in Ashburn, VA.
GigeNET is offering a free month of service with a new server in Ashburn.
Choose from 2 high performing configs, both with 100TB of bandwidth.
Higher redundancy.Lower latency.Increased capacity.Completely compliant.
http://p.sf.net/sfu/gigenet
_______________________________________________
Openrave-users mailing list
[hidden email]
https://lists.sourceforge.net/lists/listinfo/openrave-users