Optimizer failled

[Marta Carrilho]

Hello,

I've a model with 4 Constriants. When I open it in GUI it gives me this message:

"Model unable to assemble: AssemblySolver::assemble() Failed: SimTK Exception thrown at Assembler.cpp:871:
Method Assembler::assemble() failed because:
Optimizer failed with message: SimTK Exception thrown at InteriorPointOptimizer.cpp:261:
Optimizer failed: Ipopt: Maximum iterations exceeded (status -1)
Assembly error tolerance achieved: 0.0103819735916599 required: 1e-009.
Model relaxing constraints and trying again."

When I try to use Inverse Kinematics another message appears:
"Model unable to assemble: AssemblySolver::assemble() Failed: SimTK Exception thrown at Assembler.cpp:871:
Method Assembler::assemble() failed because:
Optimizer failed with message: SimTK Exception thrown at InteriorPointOptimizer.cpp:261:
Optimizer failed: Ipopt: Maximum iterations exceeded (status -1)
Assembly error tolerance achieved: 0.0103819735916599 required: 1e-009.
Model relaxing constraints and trying again.
Loaded marker file C:\Users\Robotics\Desktop\DATA\Stroke\subject01_walk1.trc (22 markers, 1799 frames)
InverseKinematicsTool Failed: AssemblySolver::assemble() Failed: SimTK Exception thrown at Assembler.cpp:871:
Method Assembler::assemble() failed because:
Optimizer failed with message: SimTK Exception thrown at InteriorPointOptimizer.cpp:261:
Optimizer failed: Ipopt: Infeasible problem detected (status 2)
Assembly error tolerance achieved: 0.0111299792380204 required: 1e-006."

Any ideia how can I solve this?

Thank you for your attention,
Marta

[Thomas Uchida]

Model unable to assemble: AssemblySolver::assemble() Failed

This error message means that you have defined constraints that are impossible to satisfy. An obvious example would be welding one foot of a human model to the origin and welding the other foot to the ground 10 meters away.

Any ideia how can I solve this?

The issue can be resolved by correcting or removing the inconsistent constraint(s). There are many troubleshooting strategies you could use. I would start by drawing the topology of the model to understand its mobilities and workspace. Alternatively, you could remove the constraints and adjust the coordinate sliders in the GUI to understand why the model cannot be assembled in the configuration implied by the constraints.

[Marta Carrilho]

Hello,

Thank you a lot for you explanation.

Is there anyway to substitute the constraints? I'm using constraints because I can't have more than one joint in a body.

Best regards,
Marta

[Thomas Uchida]

Is there anyway to substitute the constraints? I'm using constraints because I can't have more than one joint in a body.

You can have more than one joint attached to a body. For example, you can have a spherical (hip) joint at one end of the femur and a pin (knee) joint at the other. It is difficult to make recommendations without knowing what you are trying to model. You might try looking at the models used in the tutorials and examples on Confluence (http://simtk-confluence.stanford.edu:80 ... +Tutorials), the models other users have shared on simtk.org, and related threads on this forum.