Error when trying to run forward dynamics in a different pose

Provide a musculoskeletal model of the full thoracolumbar spine and rib cage for researchers to use in their investigations of spine and thorax kinematics and dynamics.
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Brandon Fugger
Posts: 4
Joined: Tue Apr 26, 2022 3:09 pm

Error when trying to run forward dynamics in a different pose

Post by Brandon Fugger » Tue Jan 24, 2023 5:10 pm

Hi there, I have changed the coordinates of this model to match a specific pose that I am aiming for, and I am attempting to use the forward dynamics tool. I am getting this error:

Integrating from 0.0 to 0.5.
ForwardTool::run() caught an exception:
Exception caught in Millard2012EquilibriumMuscle::calcMuscleDynamicsInfo from trap_inf_T4
Exception caught in Millard2012EquilibriumMuscle::calcFiberVelocityInfo from trap_inf_T4
trap_inf_T4 Fiber velocity Newton method did not converge

This only occurs when I alter the configuration of the model in any capacity. There does not appear to be any constraints that I am exceeding because I don't see any constraints defined in the model? I have done the tutorials and am following the same FD procedures done in the tutorials

Any help is greaty appreciated
Brandon


edit: This error seems to only occur when I try to add a ForceReporter to the FD settings?

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Jacob J. Banks
Posts: 88
Joined: Tue Jul 15, 2014 5:17 am

Re: Error when trying to run forward dynamics in a different pose

Post by Jacob J. Banks » Wed Jan 25, 2023 7:04 am

Hmmm...
Unfortunately, I (and really 'we') don't have a lot of experience using the forward dynamics tool with our model. So, I can't say that I am that familiar with this particular error. However, I have a few ideas of what may be the problem:
- That muscle tendon actuator attaches to the scapula. Try welding/locking the scapula position (unless that is what your interested in), to see if that is the problem. The DoF in the scapula are not all 'physiological', but rather necessary to connect things.
- While this isn't a permanent solution, try removing that MTA and if it works then (may have to increase some reserve actuator limits).
- Try applying really generous (flat) FL and FV curves.

What sort of movement are you trying to sim?

That's all I have right now. Let me/us know how that does or if you have any further questions.
Jake Banks

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