Max isometric force violation with Static Opt

[Joseph Alston]

I am running static optimization on my model and I came across a problem. In the results, all of the muscle forces are just fine, except one. This one muscle has a max isometric force of 12.927. However, in the results, the force of this muscle peaks to about 30. All other muscle stay well below their max isometric force. Why is this one not?

[Ayman Habib]

Hi Joseph,

By construction, Static Optimization limits activation of muscles to the range (.01 to 1) and these bounds cannot be disabled, so for a reasonable muscle model I'd expect that we don't go over max isometric force.

If, however, you have an example that demonstrates this behavior then please report a bug using the Help/report-a-bug option in the application. Please make sure to include the model, setup files and any data files necessary to reproduce the bug. Package all the files as one zip file and attach it to the bug report.

Thanks,
-Ayman

[Joseph Alston]

Ayman,

Thank you for your response. I have reported the bug and have included my model and inputs.

I was looking over my model and inputs trying to find where I might have added something that might have caused this problem. In my search the only thing that I could find was the "ControlLinear" default. The values I have are 0.01 to 1.0. If I were to change those default would that cause my result to change accordingly? Like if I changed the upper limit to 2, could the results show the muscles peaking out at twice the max isometric force specified for each muscle?

Also is there some way to specifiy different limits on the linear controls? If so, what would it look like?

Thank you again for your respose.
I hope this problem isn't ruining your holidays.
Joseph