On Monday 23 June 2008 14:09:37 threelight wrote:
> I'm currently working with the ChainIkSolverVel_pinv-class to calculate the
> inverse velocity for a robotic arm with 7 joints. After executing
> ChainIkSolverVel_pinv::CartToJnt I have only 6 joint velocities. The
> velocity of joint 7 is always 0. I've tried this for many end effector
> velocities and joint values (= input parameters of CartToJnt) but the value
> of the 7th joint stays 0. So, I guess that CartToJnt calculate only 6
> joints to avoid needless calculations of the other joints (= avoiding
> redundancy)? Is that true?
No, the algorithm is based on a pseudo-inverse of the robot jacobian, it
should distribute the velocity equaly over all joints if possible.

What version of KDL are you using?

There was bug in the pseudo-inverse code, it should be fixed in kdl-trunk. I
tested the algorithm on a chain with 8 joints, all jointvelocities were
different from zero.

Ruben