I don't believe the markers in the model are the current set we use. I've attached a marker file that you can replace that set with that will coincide with what we are currently doing. I've also included a CCC model that is necessary to reduce the degrees of freedom of the spine from 51 to 6. Otherw...

https://simtk.org/projects/emg_opt_tool
The EMGopt_OS40.m script from this project should give you a general idea of the procedure. Let me know if you have any questions.
Jake Banks

Yes, that is a more elegant and better way of putting it (e.g., force/unit control).
It should only be viewed as a 'maximum force' in the same way the MTAs treat it as a 'maximum force'... as force/unit control. Sorry for any confusion.
Jake Banks

Another thing I neglected to state in my initial response... is that it is difficult/not well established how to model fatigue (if you had observable kinematic changes, that would be another thing... could also may enforce some muscle recruitment changes). So keep that mind.
Jake Banks

In a word... yes. The biggest 'issue' would be having some kinematics to track/use. If don't have that you could always just look at it statically. As adding the video cam, all you would do is add/weld/attach a mass of known inertia properties to where you want on the model simulating the video cam....

How long is "quite a long time"? What model are you using? Have you made any modifications to it (e.g., welding a joint?). Reason I am asking, is that I've noticed IK can take up to 10x longer if you lock certain joints. Marker weighting can also have some impact on solve time, but it doesn't seem t...

Ross, My experience informs me that the 'optimal force' is really in fact the 'maximum force'. Therefore, in your desired application I would set the 'optimal force' to 10N and max activation to 10 (so it would take a "u" of 10 to get 100N). As I am sure you can deduce, setting optimal force/torque ...

Sorry for the delayed response... sort of forgot I replied to a post! 1 & bonus) I don't really have much to add, but I would challenge you to rethink your research question &/or design. From the information provided, your results would be very dependent upon marker weighting, which as I as stated p...

Without seeing your setup, I would suspect something is awry with your external forces (these files are, at times, tricky to make and then assign to segments). Look at the Inverse Dynamic results to confirm those are symmetric, and then go from there.
Jake Banks

1) Aside from the advice provided in the online tutorial, all I can add is that in my experience Marker Weighting is often "more art than science" and that it depends on what your research question is. Use an educated guess to set your weights and then try some modifications out to see how that impa...