Synergy Plugin with Lerner model

Provides an OpenSim plug-in for coupling muscle activity with static optimization for synergy-based control or other applications.
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George Giarmatzis
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Joined: Fri Sep 27, 2019 2:08 pm

Synergy Plugin with Lerner model

Post by George Giarmatzis » Sat Apr 11, 2020 3:12 am

Dear,

I have managed to run the Synergy plugin through Opensim 3.2-32bit, using a scaled Lerner model (92 muscles) and kinematics/GRF data from Cams-Knee project. Although standard Static Optimization (SO) routine runs smoothly without errors, when running SO with synergy plugin with an identity matrix (no change in weights) I get errors in every frame - the optimizer cannot find solution.
Also, muscle forces between the two workflows do not match - as opposed to what is stated by the authors.
An example of the error follows:
time = 5.308 Performance =3.74146 Constraint violation = 3.73172
SimTK Exception thrown at InteriorPointOptimizer.cpp:261:
Optimizer failed: Ipopt: Maximum iterations exceeded (status -1)
OPTIMIZATION FAILED...

StaticOptimization2.record: WARN- The optimizer could not find a solution at time = 5.31633

Now matter how I change all parameters (optimizer_convergence_criterion,optimizer_max_iterations, etc) , I get the same errors. Any help is welcomed.
An example setting file can be downloaded from here.
https://drive.google.com/open?id=1T-2ZH9LzPXr3dE_pjiNOosKZr6Dz-FPd

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