Hi Peter
Welcome to the group
The coordinate system for the segments in the shoulder follows the
ISB proposal from Frans C.T. van der Helm please see
http://www.fbw.vu.nl/research/Lijn_A4/shoulder/isg/proposal/protocol.
html
for the details
It is correct that the
variable “Main.Study.Output.Model.HumanModel.Right.ShoulderArm.Jnt.GH
LinCon.Reaction.F”
is the GH reaction force
By default the reaction are measured in the scapula coordinate
system but you may easily change this to the humerus coordinate
system if you want. This you can do in the following
file “BRep/Aalborg/Arm3D/Jnt.any”, please find the line
“AnyKinLinear GHLin =…”
You may then replace it by these lines
AnyKinLinear GHLin = {
AnyRefNode &scapula_gh = …Seg.Scapula.gh;
AnyRefNode &humerus_gh = …Seg.Humerus.gh;
//Add a blue coordinate system at the scapula gh node
scapula_gh={AnyDrawRefFrame drw={RGB={0,0,1};};};
//Add a red coordinate system at the scapula gh node
humerus_gh={AnyDrawRefFrame drw={RGB={1,0,0};};};
Ref=1; //use this for shifting between the two ref systems:
scapula=0, humerus=1
};
This will add a blue coordinate system in the scapula gh node and a
red coordinate system in the humerus gh node. The “Ref” object can
be used for shifting which of the two coordinate system should be
used as the reference system.
If you want to measure in neither the scapula nor humerus coordinate
system this is also possible. This can be done by defining a new
node with another orientation and use the AnyForceMomentMeasure
command which can be used for measuring forces and moments in any
coordinate system. Please see the AnyBody reference manual for the
details http://www.anybodytech.com/fileadmin/doc/AnyBodyRefManual.pdf
I hope this answered your questions, otherwise please do not
hesitate to ask again.
Best regards
AnyBody Technology Support
— In anyscript@yahoogroups.com, “peterwesterhoff”
<peterwesterhoff@y…> wrote:
> Hi anyscript-group,
> My Name is Peter Westerhoff and I am working on a project
developing an
> instrumented Shoulder Prothesis to measure the forces and Moments
in
> the glenohumeral joint at the Biomechanics Lab of the Charite
Berlin
> Campus Benjamin Franklin. More Information about the project and
> impressions of the first measurements can be seen at
www.biomechanik.de
> In this context I have my first question about one of the
Application
> in the repository. Is it right that the
>
variable “Main.Study.Output.Model.HumanModel.Right.ShoulderArm.Jnt.GH
Lin
> Con.Reaction.F” specifies the Glenohumeral contact Force? I was
> wondering about the Graph with a high force in X-Direction and
almost
> no Force in z and y Direction. Is it right that the X Direction
(red)
> points forward in this joint coordinate system like described in
the
> ISB Recommendation?
> So far by now, thanks in advance
> Peter