L5Sacrum joint in FDK

Main Forum
1

Hello,

I would have a couple of quick questions on lumbar joints: I am using the SpineFixationWithForceDepKinematics model (AMMR V. 1.6.2) and I noticed in the FDK driver definition the L5Sacrum joint is commented out to avoid over-constrained situation. Therefore I was wondering: how is it controlled? How can I modify its behavior when using FDK? For example for the other joints I can choose which ones of the 3 DOFs define as ForceDep, or I can exclude them from the FDK driver. How can I have the same control on the L5Sacrum joint?

And also, the spherical joint is a point constrain; is there any way to define a ball and socket joint in which the ball is not a point but an actual sphere with its own user-defined radius?

Many thanks,

Michele

2

Hi Michele,

I answered your first question in another thread. But the answer refers to this thread.

Secondly, what are you trying to achieve? We have a THR example, which uses a contact ball and socket joint to model a THR implant, but it requires using FDK, which is somewhat heavy as you already know.

Kind regards,
Pavel