ikine 7 DOF

[Alex Smith]

Hi, 

I am trying to use a 7DOF robot in simulink control model with cartesian trajectory. However, there is a problem with the ikine block; the mask vector asks for as many 1's as there are DOFs, but complains that the maximum number of elements in the mask vector is 6. Is there a way to get past this? 

Regards,

Alex

[Peter Corke]

can you send the robot definition and cut/paste the error message

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[Nico Scheiffert]

Maybe this paper helps you:

 

http://cdn.intechweb.org/pdfs/12671.pdf

[Alex Smith]

I've fixed it now by looking under the mask of the ikine block and removing the M option in the ikine call. The solver was having problems as well but that was fixed by adding 'pinv' as the option to the ikine call. Here is the definition (attached) and error messages anyway. 

When M = [1 1 1 1 1 1 1]:

Mask matrix should have 6 elements

When M = [1 1 1 1 1 1]:

Mask matrix must have same number of 1s as robot DOF

Alex

[Alex Smith]

Also, I am going to use the pseudo  inverse jacobian to calculate joint velocites, then integrate for joints as the plan is to only move two joints. 

Alex

[Peter.I.corke]

I like it when people fix stuff!  Thanks.

The mask corresponds to Cartesian not joint dof, so must have 6 elements.

I'll add a checkbox option for this block to enable pinv

Peter.

Sent from my iPhone

<iCub.m>

[Alex Smith]

That sounds good. It feels good to fix stuff too!

Alex

[Erik van Oene]

When moving only 2 joints, I suggest to use only the part of the Jacobian matrix associated with those two joints... This will result in a more optimal solution, as it calculates the solution by only changing those 2 joints. Otherwise all joint velocities will probably be nonzero, however you do not use them..

Erik

Op vrijdag 25 januari 2013 12:37:42 UTC+1 schreef Alex Smith het volgende:

[Alex Smith]

Thanks Eric, this was my plan anyway... And it works really well! 

Alex

[blackp...@gmail.com]

Hi I know that this is an old post but I'm doing a similar thing and a reference would be useful for me, could you share your final source code for this thing?
thank you very much
Daniel