Problem with InverseDynamicsAnalysis

Hi,

I’ve been fooling around with a 1-arm wheelchair model trying to get
it to run driven by Vicon motion analysis data and force data from
push rims. Fortunately, I can get the model to compile and establish
SetInitialConditions, however I can’t get the model to run an
InverseDynamicsAnalysis because the simplex solver does not satisfy
all constraints (or something along those lines). I have uploaded the
file - SarahArmModel - Muscles.rar - which I believe is a zip file.
At least it appears to be a zip file on my work console. If you could
help me out with this I would really appreciate it. I think that the
problem may be in the Environment.any file, however I have pretty much
copied previous work and I can’t get it to work.

Any help would be appreciated!

Thanks so much,
Sarah

Hi Sarah

I have taken a look at your model i think the problem is in the environment
file

If you look at the this driver

AnyKinEqSimpleDriver WheelRightDr = {

 AnyRevoluteJoint &Joint = .HubRight;

 DriverPos = {30*pi/180};

 DriverVel = {-1.0/0.3048};

 Reaction.Type = {0}; // Let applied moment through

};

You will see that the reactions is switched off, this was ok when the hands
was connected to the rims using a spherical joint but this is not the case
anymore.

In you model the load is applied though the dummy segments not through the
wheels. So I think you need to switch on the driver again, otherwise there
is nothing to carry the wheel moment.

If you look at the model in the repository 6 there are two wheel chair
models

WheelChair: here the hands are connected to the rims using a spherical joint
so in this case the reactions should not be there

WheelChairRancoo: This model is very similar to yours, in this model there
is no real joint between the hands and the rims, so here the reaction is on.

I hope this helps solve your problem

I was not able to load your model, because I had problems finding a matching
repository? So if this do not help please also state which version of
AnyBody you are using, then it is easier to obtain the same conditions as
you have.

Best regards

Søren, AnyBody Support


From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com] On Behalf
Of Sarah R. Sullivan
Sent: 4. oktober 2006 01:52
To: anyscript@yahoogroups.com
Subject: [anyscript] Problem with InverseDynamicsAnalysis

Hi,

I’ve been fooling around with a 1-arm wheelchair model trying to get
it to run driven by Vicon motion analysis data and force data from
push rims. Fortunately, I can get the model to compile and establish
SetInitialConditions, however I can’t get the model to run an
InverseDynamicsAnalysis because the simplex solver does not satisfy
all constraints (or something along those lines). I have uploaded the
file - SarahArmModel - Muscles.rar - which I believe is a zip file.
At least it appears to be a zip file on my work console. If you could
help me out with this I would really appreciate it. I think that the
problem may be in the Environment.any file, however I have pretty much
copied previous work and I can’t get it to work.

Any help would be appreciated!

Thanks so much,
Sarah

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