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List:       orocos-users
Subject:    [Orocos-users] Question about IK Solver
From:       ruben.smits () mech ! kuleuven ! be (Ruben Smits)
Date:       2010-03-09 8:09:32
Message-ID: c2ec65791003090009k31f64090m32cb84e2051e3174 () mail ! gmail ! com
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On Tue, Mar 9, 2010 at 4:18 AM, Benjamin Cohen <bencohen2 at gmail.com> wrote:
> Hey,
> Below is my question about the?ChainIkSolverPos_NR class.?I'm not sure if
> it's clear....if not I'll try to explain it again more clearly.
> In my chain I have segments A,B,C,D,E.?(I'm using CartToJnt (const JntArray
> &q_init, const Frame &p_in, JntArray &q_out))
> I want to be able to?solve for an IK solution for a pose of 'E' in frame 'A'
> and allow the solver to search for a solution but without using joint 'A'. I
> want it to search for a solution by just changing the joint angles
> corresponding to B,C,D,E in q_init. (So, 'A' in q_out will be guaranteed to
> be the same as the value for 'A' in q_init.) I know this may result in
> situations where it won't be able to find a solution but I that shouldn't be
> often for my use case.
> Is there a way to do this?

There is no intelligent way to tackle this without changing the code
of the ChainIkSolverPos_NR and even the ChainIkSolverVel class to take
into account locked joints.

What you can do is create a chain that only contains joints for
segments BCDE and a Joint::None for segment A, but this would probably
only make sense if the value of joint angle A does not change.

Ruben

> thank you for your time,
> -- ben
>
> p.s. I've been using the KDL for over a year now and It made my life a whole
> bunch easier. thanks!

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