Joint of the Shoulder

Hi AnyBody,

I’m trying to modell simple motions of the arm. I use Repository5.beta. Well the
KinematicAnalysis works fine but when adding the muscles and doing the
InverseDynamicAnalysis it doesn’t work. I’m using the StandingModel. The first
motion where I get troubles is Abduction/Adduction of the GH joint with straight
arms. The driver is the inclination of humerus and I give both arms the same
motion so that the body is symetric. So, when doing only abduction/adduction I
thaught there will be no problems with the comdriver. The center of mass doesn’t
change. But when starting from vertical position of the arms the study stops
allready when humerus has an inclination more than 18 degrees from vertical
position. I get the result that the solution does not satisfy all constraints. I
know what it means but don’t know where to make a change.

Study : Muscle recruitment analysis failed, simplex solver reports that
solution does not satisfy all constraints.

Sometimes I get also following answer which I don’t understand:

Unexpected exception in the library OOSol : OOSol exception : Maximal number of
iteration was exceeded in OOScg::solve :

I have thaught of the joint of the shoulder. It is actually a combination of
several joints. But the AnyKinMeasureOrg in JointsAndDrivers.any of the
StandingModel contains only the GH joint. So when doing the KinematicalAnalysis
I see in the model view that the other joints of the shoulder are stiff even
when the inclination of humerus is more than 90 degrees (hands above head). I
think this isn’t really possible. Is this why the solution doesn’t satisfy all

Another problem is how to put loads in the hands of the modell, (like exercising
with a 5-kilo-weight). It sounds easy but I’m not sure were to make a change. In
the end of JointsAndDrivers.any there is a folder with loads.
AnyFolder MannequinLoads
Is this where to make the changes?

Also when I run the model I get lots of warnings but I think they are not the
main problem.

Hope you can send me some brilliant answers to my questions.


[Non-text portions of this message have been removed]

Hello Signe,

Not having seen your model, my best guess is that the problem comes
from an unfortunate choice of solver for the problem at hand. Please
have a look at the StandingModel.main.any file. Go to the bottom and
find the specification of the solver. Change it to the following, if it
is not like this already:
RecruitmentSolver = MinMaxNRSimplex;

Pease ask again if this does not solve the problem.

(If this is your problem, then it is solved in the new version of the
system, which has more robust solvers)

Best regards
AnyBody Support