StandingLift - Failed to resolve force-dependent kinematics

Main Forum
1

Hello,

I am working on the StandingLift model, which I modified by including the lumbar ligaments and the FDK drivers for the lumbar spine that I copied from the Spine Fixation Model.
When I run a simple 1-step static simulation of the standing model with the box in front of the human model, I get this error message:
Failed to resolve force-dependent kinematics. Too many iterations used (final force error = 5.350453E+001). Continue anyhow…

(If I also try to use FDK on translational DOFs of the lumbar joints the final force error is in the order of E+003).

Could you please advice on why I am getting that error, and what I should try to investigate/modify in order not to have it?

Many thanks,

Michele

2

Dear Michele,

I may not be able to give you the best advice on your model but based on what your wrote here it seems that FDK solver could not reduce the amount of the force error less than the force tolerance.

Simply speaking, your force error is too high and maybe there are some lacks of necessary stiffness around FDK degrees of freedom to fit the force balance with muscles and joint reactions.

If you can upload your model in the debug section then we may be able to try to have a look at your model:
http://forum.anyscript.org/forumdisplay.php?f=21

Best regards,
Moonki

3

Hello Moonki,

thank you for your answer. As you suggested, I uploaded the model in the Debug section. I have not modified the stiffness already present in the repository model, but I may have done something wrong when implementing FDK in the Standing Lift model.

Thanks again,

Michele