RRA output error

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Quinten Humphrey
Posts: 36
Joined: Mon Feb 08, 2021 2:36 pm

RRA output error

Post by Quinten Humphrey » Wed Sep 22, 2021 3:42 pm

Hello all, I am trying to execute RRA on my model. As you can see in the first image, the L3 and L4 vertebras begin deviating.
Screenshot (89).png
Screenshot (89).png (616.75 KiB) Viewed 354 times

At a certain time step, my model freezes and I notice that the whole lumbar spine clumps together. Which can see in the next image.
Screenshot (90).png
Screenshot (90).png (484 KiB) Viewed 354 times
Eventually, RRA stops and I receive the following error.
CMC.computeControls: ERROR- Optimizer could not find a solution.
Unable to find a feasible solution at time =
Model cannot generate the forces necessary to achieve the target acceleration.
Possible issues: 1. not all model degrees-of-freedom are actuated,
2. there are tracking tasks for locked coordinates, and/or
3. there are unnecessary control constraints on reserve/residual actuators

What I have done to configure each issue:
1. I believe all of the model's degree-of-freedoms are actuated because the coordinates are all included in the RRA file, unless I am misunderstanding what they are talking about.
2. I have hidden the tracking tasks for the locked coordinates on the RRA task file.
3. I assume this involves the RRA control constraints file, which I do not run with the RRA tool because I read in another post that it isn't necessary to include.

Other things I have tried:
- Adjusted the weights in the tracking task for the lumbar vertebra
- Adjusted the optimal force for the lumbar vertebra

I appreciate any feedback from you.
Regards,
Quinten

User avatar
Quinten Humphrey
Posts: 36
Joined: Mon Feb 08, 2021 2:36 pm

Re: RRA output error

Post by Quinten Humphrey » Thu Sep 23, 2021 7:06 pm

I'm responding to my own post as I have resolved the issue and am sharing the solution in case anyone else comes across this problem. I added constraints for the lumbar and cervical spines.

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