GHReactions Translation Measurement

Main Forum
1

Hello Everybody,

My goal is to measure translation in the GH joint, I know that the pushing muscles prevent the joint from doing that.

My question is, why does my measured translation doesnt even slighlty change if I weaken those muscles to down to 5? Or do I measure the translation in a wrong way?

Is switching to FDK the only possibility to be able to measure the translation, or are there others?

cheers, Marc

2

Dear Marc,

If you see the ‘Jnt.any’ file in the ‘AMMR\Body\AAUHuman\Arm’ then you can find these pieces of code:

AnyKinLinear GHLin = {
  AnyRefNode &scapula_gh = ..Seg.Scapula.gh;
  AnyRefNode &humerus_gh = ..Seg.Humerus.gh;
  
  Ref=0; //use this for shifting between the two ref systems: scapula=0, humerus=1
};

AnyKinEq GHLinCon = {
  AnyKinMeasure &GHLinCon = .GHLin;
  Reaction.Type={Off,Off,Off};
};

So this GHLinCon will make this GHLin measure always zero, you will not see any translation in the GH joint.

If you want to see the translation in the glenohumeral joint, you can try to change this GHLinCon as ‘force dependent’ and also you should introduce a contact and some stiffness(ligaments).

I hope this may be helpful to you.

Best regards,
Moonki