Modeling and simulation of the human legs

Hi !

We are a group of students working on a project which deals with biomechanics :
we have to model and to simulate the human legs (and especially the knee), and
if it is possible dynamicly in a gait cycle.
Our professor chose to work with the AnyBody Simulation System. We began to work
the tutorials but we don’t know if it can do what we want it to do : our
project.

We saw in some pics in the documentation available that there is already a study
of the human legs and the knee. Can you please indicate us where we can find it,
and if our project can be done with AnyBody ?

Thanks in advance and best regards,

Rafik REZINE
for the group


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Hello Rafik,

Welcome to the group. Yes, you can certanly do gait modeling with
AnyBody. The best way is to grab a suitable model from the
repository and impose a gait pattern on it. The two issues you need
to address are the following:

  1. Driving the model with motion capture data

This is accomplished by defining AnyRefNodes on the model
correspondng to your marker positions, and then driving them with
AnyKinEqInterPol drivers. It might be a good idea to do the building
block tutorial and the driver tutorial before you attempt to create
the gait model.

Another user recently aske us about this , and I developed a small 2-
D example to demonstrate the technique. I have zipped the model and
uploaded it to the files section of the group. Please feel free to
grab it from there.

  1. Applying ground reaction forces

The basic idea is to define a segment in the model corresponding to
the force plate in your gait laboratory. The segment should be
massless. Subsequently you apply as many external forces and moments
to the plate as it has degrees of freedom. Finally you create an
AnyReacForce between the force plate and the foot. This will allow
the foot to move independently of the force plate while transferring
the forces applied to the force plate to the foot.

In the current version of the system, interpolated ground reaction
forces require a workaround. We have an udate due very soon that
will alleviate this problem. Please write again when you have the
kinematics working, and we can advice you about either using the
workaround or getting an update.

The project described in the AnyGait section on the homepage is a
more long term venture with an aim to create a fully automated
interface. This is unfortunately not operational yet. We are hoping
that the AnyBody Research roject will get funding to complete this
work soon.

Best regards,
John,
AnyBody Support.

— In anyscript@yahoogroups.com, Rezine Rafik <rafik_rezine@y…>
wrote:
>
> Hi !
>
> We are a group of students working on a project which deals with
biomechanics : we have to model and to simulate the human legs (and
especially the knee), and if it is possible dynamicly in a gait
cycle.
> Our professor chose to work with the AnyBody Simulation System. We
began to work the tutorials but we don’t know if it can do what we
want it to do : our project.
>
> We saw in some pics in the documentation available that there is
already a study of the human legs and the knee. Can you please
indicate us where we can find it, and if our project can be done
with AnyBody ?
>
> Thanks in advance and best regards,
>
> Rafik REZINE
> for the group
>
>
> ---------------------------------
> Créez gratuitement votre Yahoo! Mail avec 100 Mo de stockage !
> Créez votre Yahoo! Mail
>
> Le nouveau Yahoo! Messenger est arrivé ! Découvrez toutes les
nouveautés pour dialoguer instantanément avec vos amis.Téléchargez
GRATUITEMENT ici !
>
> [Non-text portions of this message have been removed]

Hello anyscripers and anyscriptress !
Merry Christmas

I have a problem using some of the projects of the
repository (AnybodyRepository4).
Some of the projects work correctly, but the others
(like the project Knee load and the project PushUp),
don’t works.

For example, for the project Knee load, I opened the
file kneeload.main, and cliqued on the M<-S button,
the following message appeared :

ERROR : D:\mini projet
structure\AnyBodyRepository4\AnyBodyRepository4\ARep\Aalborg\KneeLoad\KneeLoad.M
ain.any(87)
: MinMaxNRSimplex : Unresolved object.
Model loading skipped

Also for the project PushUp, I opened the file
PushUp.main, and cliqued on the M<-S button, the
following message appeared :

ERROR : D:\mini projet
structure\AnyBodyRepository4\AnyBodyRepository4\ARep\Aalborg\PushUp\PushUp.main.
any(71)
: MinMaxNRSimplex : Unresolved object.
Model loading skipped

So, can you tell please what’s going bad here ? May be
I didn’t opened the right file ?
Thank you for your help.

Rafik

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Hello Rafik,

It looks like the problem is that you are using an earlier version
of the AnyBody Modeling System that is not compatible with the
current version of the repository. The repository requires version
1.3 of the software.

Best regards and Happy New Year,
John
AnyBody Support

— In anyscript@yahoogroups.com, Rezine Rafik <rafik_rezine@y…>
wrote:
>
> Hello anyscripers and anyscriptress !
> Merry Christmas
>
> I have a problem using some of the projects of the
> repository (AnybodyRepository4).
> Some of the projects work correctly, but the others
> (like the project Knee load and the project PushUp),
> don’t works.
>
> For example, for the project Knee load, I opened the
> file kneeload.main, and cliqued on the M<-S button,
> the following message appeared :
>
> ERROR : D:\mini projet
> structure\AnyBodyRepository4\AnyBodyRepository4
\ARep\Aalborg\KneeLoad\KneeLoad.Main.any(87)
> : MinMaxNRSimplex : Unresolved object.
> Model loading skipped
>
> Also for the project PushUp, I opened the file
> PushUp.main, and cliqued on the M<-S button, the
> following message appeared :
>
> ERROR : D:\mini projet
> structure\AnyBodyRepository4\AnyBodyRepository4
\ARep\Aalborg\PushUp\PushUp.main.any(71)
> : MinMaxNRSimplex : Unresolved object.
> Model loading skipped
>
> So, can you tell please what’s going bad here ? May be
> I didn’t opened the right file ?
> Thank you for your help.
>
> Rafik
>
>
>
>
>
>
>
> Découvrez le nouveau Yahoo! Mail : 250 Mo d’espace de stockage
pour vos mails !
> Créez votre Yahoo! Mail sur http://fr.mail.yahoo.com/