UWLigaments + Joint Reaction Analysis

Provide easy-to-use, extensible software for modeling, simulating, controlling, and analyzing the neuromusculoskeletal system.
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Karen Fitzgerald
Posts: 24
Joined: Mon Sep 08, 2014 6:03 am

UWLigaments + Joint Reaction Analysis

Post by Karen Fitzgerald » Mon Oct 07, 2019 6:43 am

Hi everyone,

Has anybody included ligaments (UWLigament Model) in there models and then tried using the Joint Reaction Analysis tool?

I've tried two different workflows which result in different force results.

Workflow 1:
IK - SO - remove ligament results from .sto file - JR (with ligaments included as UWLigament type)

Workflow 2 :

IK - SO - remove all but ligament total force from .sto file - JR (with ligaments as Thelen2003Muscle/Millard2012EquilibriumMuscle* type)

*both give the same result.

If anyone could shed some light on whether either of these methods is correct or if they are both wrong what is the correct approach that would be really helpful?

Thanks for your help!

Karen
Tags:
OpenSim 3.3 and Earlier
GUI
Windows
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Dimitar Stanev
Posts: 1096
Joined: Fri Jan 31, 2014 5:14 am

Re: UWLigaments + Joint Reaction Analysis

Post by Dimitar Stanev » Mon Oct 07, 2019 12:58 pm

I have the impression that UWLigament is a force, therefore if it is included in the model as a component it doesn't matter whether you prescribe its force through a .sto file. During joint reaction analysis the passive forces (ligaments) are automatically included in the calculations. You can verify this by disabling the ligaments prior to running the analysis.

As for the second case, can you specify how the ligaments are being modeled?
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