Search found 44 matches

by Edith Arnold
Thu Jan 10, 2013 12:40 pm
Forum: The Musculoskeletal Modeler's Kitchen
Topic: Source of Error Tolerances
Replies: 1
Views: 397

Re: Source of Error Tolerances

Hello Mike, These are mostly from practical experience. This is a more official source with additional information: http://simtk-confluence.stanford.edu:8080/display/OpenSim/Modeling+and+Simulation+Best+Practices This reply is very late because several of us who monitor this page got caught up in gr...
by Edith Arnold
Thu Mar 08, 2012 3:46 pm
Forum: OpenSim
Topic: Multiple IK trials
Replies: 2
Views: 203

Re: Multiple IK trials

Hi Hassan,

I wrote up some examples of how to run a batch of IK (or any other tool) using setup files and matlab here:
http://wiki.simtk.org/modelerskitchen/S ... processing

-Edith
by Edith Arnold
Tue Mar 06, 2012 6:42 pm
Forum: OpenSim
Topic: Parameters( activation1,activation2,damping)?
Replies: 1
Views: 570

Re: Parameters( activation1,activation2,damping)?

Hi Jae, The best source for the theory behind the Schutte muscle model is Lisa Schutte's dissertation, appendices 2 and 3. Using musculoskeletal models to explore strategies for improving performance in electrical stimulation-induced leg cycle ergometry LM Schutte - 1992 - Stanford University Accord...
by Edith Arnold
Tue Nov 29, 2011 6:13 pm
Forum: The Musculoskeletal Modeler's Kitchen
Topic: Model Geometry Measurement/Modification
Replies: 1
Views: 378

Re: Model Geometry Measurement/Modification

A hacky way to do this would be to place a marker at the joint centers, create a "Measurement" in the scale tool between these markers, then apply manual scaling to change the segment length the desired amount. I've done this when I have functional joint center measurements at the hip by placing a m...
by Edith Arnold
Tue Nov 29, 2011 6:07 pm
Forum: OpenSim
Topic: Zeroing Muscle Activation
Replies: 4
Views: 644

Re: Zeroing Muscle Activation

Hi guys, This explanation of solving for equilibrium states is not quite correct. There are two different types of equilibrium being discussed here and there is ambiguity in the tag name that obfuscates the issue a bit. Type 1: The muscle and tendon are in equilibrium such that (Muscle active force ...
by Edith Arnold
Wed Oct 26, 2011 2:05 pm
Forum: OpenSim
Topic: Warning message in CMC V2.4
Replies: 4
Views: 634

Re: Warning message in CMC V2.4

Hi Ruoli, I don't think this is what is affecting your compute time. This message appears in patlig because that muscle's FMax is 0 (it's a hack from when there weren't ligaments in OpenSim). It's true that there's a small force and that's appropriate. I'm not sure why it's appearing in pectineus, e...
by Edith Arnold
Wed Oct 26, 2011 11:27 am
Forum: OpenSim
Topic: Increasing muscle strengths
Replies: 2
Views: 315

Re: Increasing muscle strengths

Hi, Yes, max_isometric_force is the parameter that people are referring to when they say to change muscle strength. Generally, unless there is reason to believe that the subject you are modeling has an atypical force distribution, I think it is best practice to increase all the muscle forces by the ...
by Edith Arnold
Wed Sep 07, 2011 5:23 pm
Forum: Lower Limb Model 2010
Topic: bug fixes in v2.1 address knee_angle and wrap visibility
Replies: 0
Views: 402

bug fixes in v2.1 address knee_angle and wrap visibility

Two bugs in the 2-leg, OpenSim version of the lower limb model were recently brought to my attention, and I have posted a new version to correct these issues. v2.1 is now available for download. The bugs and fixes are: Bug: The range of the knee_angle_r and knee_angle_l coordinate was inappropriatel...
by Edith Arnold
Fri Aug 19, 2011 3:03 pm
Forum: The Musculoskeletal Modeler's Kitchen
Topic: Batch Processing Example
Replies: 0
Views: 302

Batch Processing Example

I have added an example of how to do batch processing of open sim tools in matlab to the downloads section. Please let me know if you have any questions or suggestions.
by Edith Arnold
Thu Mar 17, 2011 6:15 pm
Forum: The Musculoskeletal Modeler's Kitchen
Topic: Model Validation
Replies: 2
Views: 610

RE: Model Validation

<t>Hi Shiuan-Lin,<br/> Taking a subject's joint moment data with a dynamometer and adjusting the model's Fmax values would be a good way to validate a model if you want to argue that it is subject specific, but I think most people do not take this step. Rather, they follow a procedure more like the ...