RRA problem with external force

[Roberta Furone]

Dear all,
I have a problem with RRA tool. If I use the external force in the toolbox the RRA doesn' t work instead without it works. The file external is the same of the model 'leg6dof9musc".

Do you have an idea to solve this problem?
Thanks a lot.

[Ayman Habib]

Hi Roberta,

Without your model and data files it'd be hard to help you troubleshoot. It's possible the external loads file you're using from the example refers to segments that are not in your model. Typically you use forces that you measured experimentally (so you know where to apply them, what frame they're collected in etc.) rather than a stock external loads file.

Can you step back and explain what you're trying to accomplish, and why you need to run RRA to begin with?

Best regards,
-Ayman

[Roberta Furone]

Thanks for the answer...
I use the model Rat Right Hindlimb and I have real experiments from vicon.
The external forces are applied to the 'foot' of the rat and expressed in reference to the body 'ground'. I would like to do RRA beccause I need the muscles activation an I read that trough RRA I can do CMC in order to obtain better solutions, better than the Static Optimization.

Now I tried to do RRA without external force it doesn't crash but the CMC doesn't work: I have this kind of error
<<Fatal Error: Function is not (fully) implemented (function = OpenSim::CMCTool::constructRRAControlSet, file = C:\Users\Kevin X\Documents\project\source\opensim\OpenSim31\OpenSim\Tools\CMCTool.cpp, line = 1009)>>

I attached two files: the first is the file to implement CMC tool, the second one the file of the external force.
I don't able to attach others files. Do you need more? can I send you from email?

Thanks a lot.

[jimmy d]

Hi Robert,

In your case I would suggest doing static optimization first. If you are testing a single limb, you may not have accounted for the other forces in the system; grf of the other limbs, overall mass, etc.

In this case it may be difficult for cmc to converge on a solution. Static optimization is an inverse method and may be more robust for your needs.

Hope that helps,
-james

[Roberta Furone]

Hi James,
thanks for the answer.
The problem is that I have only the external force of the right leg.I have done static optimitation but my results are not congruent with the real ones.

what do you think about?

Thanks.
Roberta.