Differentiate between active and passive muscle forces

[kishan srinivas indrani]

Hey ,

I am analyzing the effect of active muscles forces in an impact scenario. For this, I have used DeMers drop landing model as reference. I simulated two scenarios, one with controllers (muscle fiber stretch controller) to excite the muscles and second is without any controllers (a passive model). From the Forward Dynamics Analyses section, I selected Actuation and Muscle Analysis as required results, I got a bunch of .sto files as output. I have a couple of questions:

1. Opensim GUI shows a warning of '' 'MuscleFiberStretchController' is not a registered Object! '' and ''MuscleFiberStretchController not recognized''. Can someone tell me why does this message pop up. Should I neglect this message or is something wrong?

2. For my passive model, why does the results include activefiberforce.sto ?

3. What files should I refer to identify the effect of active muscles in my new model as compared to passive muscles in my previous model?
I appreciate your help.
Thanks

[Thomas Uchida]

1. Opensim GUI shows a warning of '' 'MuscleFiberStretchController' is not a registered Object! '' and ''MuscleFiberStretchController not recognized''. Can someone tell me why does this message pop up. Should I neglect this message or is something wrong?

Have you forgotten to load a plugin that defines the MuscleFiberStretchController class?

2. For my passive model, why does the results include activefiberforce.sto ?

I presume you're running a MuscleAnalysis. The same quantities are reported regardless of their values.