# How to constraint reaction loads

Hi

I am working on a simplified 2D lumbar spine model with 5 revolute
joints. I have the reactions loads set to “off” and I added passive
resistance to each joint. I used the AnyForceMeasure2 to calculate my
reaction loads and moment at each joint. I would like to add
constraints to my reaction loads, such as minimize moment or minimize
shear.
Can you please give me some advice on how I can constraint my
reactions?

Thanks,

Lissette

Hi Lisette

It is not in general possible to add limits to the size of constraint in
joints.

If you want the constraints to be minimized then you have to remodel these
as AnyGeneral Muscles instead, this will make them part of the recruitment
problem and they can be minimized just like any other muscle in the model.

The AnyGeneral muscles are muscles that can be applied to any measure, if
applied to a linear measure the supply force if applied to rotations they
supply moment. The muscles act in one direction you can set if the muscles
should push or pull, default is pulling. This is controlled by the
ForceDirection variable which default is “-1” by setting this to “1” you
have a muscle which is creating a push force.

If you replace a reaction of a joint with one very strong AnyGeneral muscle
in each direction then the model will work almost as before but now the
reaction force is now part of the muscle recruitment. The stronger this
muscle is, the more this problem will act as a normal constraint and the
lower the strength is the more the model will “feel the cost” of using this
muscle and try to recruit the other muscles in a way that will lower the
activity of this muscle.

So in this way you can not add an absolute limit to the constraint but you
can control it to some extend. Please be aware that this setup requires some
checking. If you want to use low strength values you should carefully check
the consequences of this on the model. If the strength is low you may end up
with a model where this muscle is defining the height of the activity
envelope, which means that the model will try in every way possible to lower
the activation of this “reaction”, this may not be a physiological muscle
recruitment criteria for the normal muscles.

Best regards

SÃ¸ren, AnyBody Support

From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com] On Behalf
Of rubertel
Sent: 02 December 2008 03:15
To: anyscript@yahoogroups.com
Subject: [AnyScript] How to constraint reaction loads

Hi

I am working on a simplified 2D lumbar spine model with 5 revolute
joints. I have the reactions loads set to “off” and I added passive
resistance to each joint. I used the AnyForceMeasure2 to calculate my
reaction loads and moment at each joint. I would like to add
constraints to my reaction loads, such as minimize moment or minimize
shear.
Can you please give me some advice on how I can constraint my
reactions?

Thanks,

Lissette

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

Hi Soren

I am not sure how to define a dummy muscle to replace all reactions.
Let’s say I would usually have a revolute joint between two segments.
Do I still define a revolute joint? and use the comand AnyReaction
Force to link it with 5 dummy muscles.
Is there an example I can look at?

Lissette

— In anyscript@yahoogroups.com, AnyScript Support
<anyscriptsup@…> wrote:
>
> Hi Lisette
>
>
>
> It is not in general possible to add limits to the size of
constraint in
> joints.
>
>
>
> If you want the constraints to be minimized then you have to
remodel these
> as AnyGeneral Muscles instead, this will make them part of the
recruitment
> problem and they can be minimized just like any other muscle in
the model.
>
>
>
> The AnyGeneral muscles are muscles that can be applied to any
measure, if
> applied to a linear measure the supply force if applied to
rotations they
> supply moment. The muscles act in one direction you can set if the
muscles
> should push or pull, default is pulling. This is controlled by the
> ForceDirection variable which default is “-1” by setting this
to “1” you
> have a muscle which is creating a push force.
>
>
>
> If you replace a reaction of a joint with one very strong
AnyGeneral muscle
> in each direction then the model will work almost as before but
now the
> reaction force is now part of the muscle recruitment. The stronger
this
> muscle is, the more this problem will act as a normal constraint
and the
> lower the strength is the more the model will “feel the cost” of
using this
> muscle and try to recruit the other muscles in a way that will
lower the
> activity of this muscle.
>
>
>
> So in this way you can not add an absolute limit to the constraint
but you
> can control it to some extend. Please be aware that this setup
requires some
> checking. If you want to use low strength values you should
carefully check
> the consequences of this on the model. If the strength is low you
may end up
> with a model where this muscle is defining the height of the
activity
> envelope, which means that the model will try in every way
possible to lower
> the activation of this “reaction”, this may not be a physiological
muscle
> recruitment criteria for the normal muscles.
>
>
>
> Best regards
>
> SÃ¸ren, AnyBody Support
>
>
>
> _____
>
> From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com]
On Behalf
> Of rubertel
> Sent: 02 December 2008 03:15
> To: anyscript@yahoogroups.com
> Subject: [AnyScript] How to constraint reaction loads
>
>
>
> Hi
>
> I am working on a simplified 2D lumbar spine model with 5 revolute
> joints. I have the reactions loads set to “off” and I added
passive
> resistance to each joint. I used the AnyForceMeasure2 to calculate
my
> reaction loads and moment at each joint. I would like to add
> constraints to my reaction loads, such as minimize moment or
minimize
> shear.
> Can you please give me some advice on how I can constraint my
> reactions?
>
> Thanks,
>
> Lissette
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

Hi Soren

I also wanted to add, that my objective is to restrict the
orientation of the resultant reaction load not necesarrily its
magnitude. For example say you have a Resultant Reaction force of
magnitude 10 at an angle of 20deg. I would like to know what muscle
loads are necesarry to restrict the resultant to act at an angle of
10deg, which is known to me. Ofcourse one is dependent of the other,
by changing teh components you change the direction of teh resultant
So in essence I know the direction of my resultant joint reactions.
Would I still need to use the dummy muscles or could I use someting
similar to the dummy segment?

Lissette

— In anyscript@yahoogroups.com, “rubertel” <rubertel@…> wrote:
>
> Hi Soren
>
> I am not sure how to define a dummy muscle to replace all
reactions.
> Let’s say I would usually have a revolute joint between two
segments.
> Do I still define a revolute joint? and use the comand AnyReaction
> Force to link it with 5 dummy muscles.
> Is there an example I can look at?
>
> Lissette
>
>
> — In anyscript@yahoogroups.com, AnyScript Support
> <anyscriptsup@> wrote:
> >
> > Hi Lisette
> >
> >
> >
> > It is not in general possible to add limits to the size of
> constraint in
> > joints.
> >
> >
> >
> > If you want the constraints to be minimized then you have to
> remodel these
> > as AnyGeneral Muscles instead, this will make them part of the
> recruitment
> > problem and they can be minimized just like any other muscle in
> the model.
> >
> >
> >
> > The AnyGeneral muscles are muscles that can be applied to any
> measure, if
> > applied to a linear measure the supply force if applied to
> rotations they
> > supply moment. The muscles act in one direction you can set if
the
> muscles
> > should push or pull, default is pulling. This is controlled by
the
> > ForceDirection variable which default is “-1” by setting this
> to “1” you
> > have a muscle which is creating a push force.
> >
> >
> >
> > If you replace a reaction of a joint with one very strong
> AnyGeneral muscle
> > in each direction then the model will work almost as before but
> now the
> > reaction force is now part of the muscle recruitment. The
stronger
> this
> > muscle is, the more this problem will act as a normal constraint
> and the
> > lower the strength is the more the model will “feel the cost” of
> using this
> > muscle and try to recruit the other muscles in a way that will
> lower the
> > activity of this muscle.
> >
> >
> >
> > So in this way you can not add an absolute limit to the
constraint
> but you
> > can control it to some extend. Please be aware that this setup
> requires some
> > checking. If you want to use low strength values you should
> carefully check
> > the consequences of this on the model. If the strength is low
you
> may end up
> > with a model where this muscle is defining the height of the
> activity
> > envelope, which means that the model will try in every way
> possible to lower
> > the activation of this “reaction”, this may not be a
physiological
> muscle
> > recruitment criteria for the normal muscles.
> >
> >
> >
> > Best regards
> >
> > SÃ¸ren, AnyBody Support
> >
> >
> >
> > _____
> >
> > From: anyscript@yahoogroups.com
[mailto:anyscript@yahoogroups.com]
> On Behalf
> > Of rubertel
> > Sent: 02 December 2008 03:15
> > To: anyscript@yahoogroups.com
> > Subject: [AnyScript] How to constraint reaction loads
> >
> >
> >
> > Hi
> >
> > I am working on a simplified 2D lumbar spine model with 5
revolute
> > joints. I have the reactions loads set to “off” and I added
> passive
> > resistance to each joint. I used the AnyForceMeasure2 to
calculate
> my
> > reaction loads and moment at each joint. I would like to add
> > constraints to my reaction loads, such as minimize moment or
> minimize
> > shear.
> > Can you please give me some advice on how I can constraint my
> > reactions?
> >
> > Thanks,
> >
> > Lissette
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>

Hi Lissette

It is actually possible to restrict the directions of the reaction forces to
be within a certain range, if they are created with the AnyGeneral muscles.

This exactly what is done in the GH joint in the shoulder!. The GH joint is
a spherical joint, which reactions have been switched off. Swithing off the
reaction is possible in all joints, by changing the following property.

Constraints.Reaction.Type, by default all its components will be on but you
can remove reactions individually from the joint.

For a revolute joint settings like
Constraints.Reaction.Type={off,off,off,on,on}; will mean that all three
forces reactions are switched off whereas the moment reactions is still on.

In the GH joint we wanted to constrain the direction of the reaction force
to fall within the glenoid cavity of scapula. To ensure this, eight pushing
muscles now acts from the gh joint rotation center onto the edge of the
glenoid cavity, to try to picture this setup it resembles the frame of a
tipi tent ;-).

Since each of the muscles can only push there is no way that the resultant
force can fall outside the cavity of the glenoid cavity.

The setup of the gh reactions can be found in the file
body/aauhuman/arm/ghreaction.any, this is a good example on how to implement
this.

Your case is not exactly the same but it resembles a lot, in my imagination
of your problem you will have to define a number of new nodes with the same
location but different rotations, but each vector which is lying in 20 deg
with wrt to horizontal. For each node you will create an AnykinLinear and a
pushing and pulling muscles acting on it. Then the solver will be able to
choose any combination of these vectors it can maximally be 20 deg because
there is no combination of vectors that can create forces above 20 deg.
This setup limits the angle not the size of the force.

When doing these kinds of models, it is a good idea to start simple

1 do a one segment model

2 apply the joint

3 remove the constraints as needed

4 apply the muscles needed, to do so you will also need to add so new nodes
with are rotated with the desired angles.

5 evaluate the results and make sure it makes sense.

I know I may sound a bit complicate, but try to look at the ghreaction.any
file it may help explain it better.

Best regards

SÃ¸ren, AnyBody Support

From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com] On Behalf
Of rubertel
Sent: 11 December 2008 00:09
To: anyscript@yahoogroups.com
Subject: [AnyScript] Re: How to constraint reaction loads

Hi Soren

I also wanted to add, that my objective is to restrict the
orientation of the resultant reaction load not necesarrily its
magnitude. For example say you have a Resultant Reaction force of
magnitude 10 at an angle of 20deg. I would like to know what muscle
loads are necesarry to restrict the resultant to act at an angle of
10deg, which is known to me. Ofcourse one is dependent of the other,
by changing teh components you change the direction of teh resultant
So in essence I know the direction of my resultant joint reactions.
Would I still need to use the dummy muscles or could I use someting
similar to the dummy segment?

Lissette

— In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com,
“rubertel” <rubertel@…> wrote:
>
> Hi Soren
>
> I am not sure how to define a dummy muscle to replace all
reactions.
> Let’s say I would usually have a revolute joint between two
segments.
> Do I still define a revolute joint? and use the comand AnyReaction
> Force to link it with 5 dummy muscles.
> Is there an example I can look at?
>
> Lissette
>
>
> — In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com,
AnyScript Support
> <anyscriptsup@> wrote:
> >
> > Hi Lisette
> >
> >
> >
> > It is not in general possible to add limits to the size of
> constraint in
> > joints.
> >
> >
> >
> > If you want the constraints to be minimized then you have to
> remodel these
> > as AnyGeneral Muscles instead, this will make them part of the
> recruitment
> > problem and they can be minimized just like any other muscle in
> the model.
> >
> >
> >
> > The AnyGeneral muscles are muscles that can be applied to any
> measure, if
> > applied to a linear measure the supply force if applied to
> rotations they
> > supply moment. The muscles act in one direction you can set if
the
> muscles
> > should push or pull, default is pulling. This is controlled by
the
> > ForceDirection variable which default is “-1” by setting this
> to “1” you
> > have a muscle which is creating a push force.
> >
> >
> >
> > If you replace a reaction of a joint with one very strong
> AnyGeneral muscle
> > in each direction then the model will work almost as before but
> now the
> > reaction force is now part of the muscle recruitment. The
stronger
> this
> > muscle is, the more this problem will act as a normal constraint
> and the
> > lower the strength is the more the model will “feel the cost” of
> using this
> > muscle and try to recruit the other muscles in a way that will
> lower the
> > activity of this muscle.
> >
> >
> >
> > So in this way you can not add an absolute limit to the
constraint
> but you
> > can control it to some extend. Please be aware that this setup
> requires some
> > checking. If you want to use low strength values you should
> carefully check
> > the consequences of this on the model. If the strength is low
you
> may end up
> > with a model where this muscle is defining the height of the
> activity
> > envelope, which means that the model will try in every way
> possible to lower
> > the activation of this “reaction”, this may not be a
physiological
> muscle
> > recruitment criteria for the normal muscles.
> >
> >
> >
> > Best regards
> >
> > SÃ¸ren, AnyBody Support
> >
> >
> >
> > _____
> >
> > From: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com
[mailto:anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com]
> On Behalf
> > Of rubertel
> > Sent: 02 December 2008 03:15
> > To: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com
> > Subject: [AnyScript] How to constraint reaction loads
> >
> >
> >
> > Hi
> >
> > I am working on a simplified 2D lumbar spine model with 5
revolute
> > joints. I have the reactions loads set to “off” and I added
> passive
> > resistance to each joint. I used the AnyForceMeasure2 to
calculate
> my
> > reaction loads and moment at each joint. I would like to add
> > constraints to my reaction loads, such as minimize moment or
> minimize
> > shear.
> > Can you please give me some advice on how I can constraint my
> > reactions?
> >
> > Thanks,
> >
> > Lissette
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>

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

Hi Soren

I was able to use the dummy muscle to control the reaction loads at
the joints. The problem I have now is that the moment at each level
seems to be random. It changes sign and increases and decreases from
one level to the next. I would like to be able to make the reaction
moment at each level a fraction of the ground reaction forces. For
example if my reaction moment at the sacrum is 5.0Nm. Then L5 should
be 4.0Nm, L3, 3.0Nm and so on. I tried turning the driver reactions
off and using a passive resistance, but the software says that the
problem is unbounded.
Is there a way to control this reaction moment?

Lissette

— In anyscript@yahoogroups.com, AnyScript Support <anyscriptsup@…>
wrote:
>
> Hi Lissette
>
>
>
> It is actually possible to restrict the directions of the reaction
forces to
> be within a certain range, if they are created with the AnyGeneral
muscles.
>
>
>
> This exactly what is done in the GH joint in the shoulder!. The GH
joint is
> a spherical joint, which reactions have been switched off. Swithing
off the
> reaction is possible in all joints, by changing the following
property.
>
>
>
> Constraints.Reaction.Type, by default all its components will be on
but you
> can remove reactions individually from the joint.
>
>
>
> For a revolute joint settings like
> Constraints.Reaction.Type={off,off,off,on,on}; will mean that all
three
> forces reactions are switched off whereas the moment reactions is
still on.
>
>
>
> In the GH joint we wanted to constrain the direction of the reaction
force
> to fall within the glenoid cavity of scapula. To ensure this, eight
pushing
> muscles now acts from the gh joint rotation center onto the edge of
the
> glenoid cavity, to try to picture this setup it resembles the frame
of a
> tipi tent ;-).
>
>
>
> Since each of the muscles can only push there is no way that the
resultant
> force can fall outside the cavity of the glenoid cavity.
>
>
>
> The setup of the gh reactions can be found in the file
> body/aauhuman/arm/ghreaction.any, this is a good example on how to
implement
> this.
>
>
>
> Your case is not exactly the same but it resembles a lot, in my
imagination
> of your problem you will have to define a number of new nodes with
the same
> location but different rotations, but each vector which is lying in
20 deg
> with wrt to horizontal. For each node you will create an
AnykinLinear and a
> pushing and pulling muscles acting on it. Then the solver will be
able to
> choose any combination of these vectors it can maximally be 20 deg
because
> there is no combination of vectors that can create forces above 20
deg.
> This setup limits the angle not the size of the force.
>
>
>
>
>
> When doing these kinds of models, it is a good idea to start simple
>
> 1 do a one segment model
>
> 2 apply the joint
>
> 3 remove the constraints as needed
>
> 4 apply the muscles needed, to do so you will also need to add so
new nodes
> with are rotated with the desired angles.
>
> 5 evaluate the results and make sure it makes sense.
>
>
>
> I know I may sound a bit complicate, but try to look at the
ghreaction.any
> file it may help explain it better.
>
>
>
>
>
> Best regards
>
> SÃ¸ren, AnyBody Support
>
>
>
> _____
>
> From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com]
On Behalf
> Of rubertel
> Sent: 11 December 2008 00:09
> To: anyscript@yahoogroups.com
> Subject: [AnyScript] Re: How to constraint reaction loads
>
>
>
> Hi Soren
>
> I also wanted to add, that my objective is to restrict the
> orientation of the resultant reaction load not necesarrily its
> magnitude. For example say you have a Resultant Reaction force of
> magnitude 10 at an angle of 20deg. I would like to know what muscle
> loads are necesarry to restrict the resultant to act at an angle of
> 10deg, which is known to me. Ofcourse one is dependent of the other,
> by changing teh components you change the direction of teh resultant
> So in essence I know the direction of my resultant joint reactions.
> Would I still need to use the dummy muscles or could I use someting
> similar to the dummy segment?
>
> Lissette
>
> — In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com,
> “rubertel” <rubertel@> wrote:
> >
> > Hi Soren
> >
> > I am not sure how to define a dummy muscle to replace all
> reactions.
> > Let’s say I would usually have a revolute joint between two
> segments.
> > Do I still define a revolute joint? and use the comand AnyReaction
> > Force to link it with 5 dummy muscles.
> > Is there an example I can look at?
> >
> > Lissette
> >
> >
> > — In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com,
> AnyScript Support
> > <anyscriptsup@> wrote:
> > >
> > > Hi Lisette
> > >
> > >
> > >
> > > It is not in general possible to add limits to the size of
> > constraint in
> > > joints.
> > >
> > >
> > >
> > > If you want the constraints to be minimized then you have to
> > remodel these
> > > as AnyGeneral Muscles instead, this will make them part of the
> > recruitment
> > > problem and they can be minimized just like any other muscle in
> > the model.
> > >
> > >
> > >
> > > The AnyGeneral muscles are muscles that can be applied to any
> > measure, if
> > > applied to a linear measure the supply force if applied to
> > rotations they
> > > supply moment. The muscles act in one direction you can set if
> the
> > muscles
> > > should push or pull, default is pulling. This is controlled by
> the
> > > ForceDirection variable which default is “-1” by setting this
> > to “1” you
> > > have a muscle which is creating a push force.
> > >
> > >
> > >
> > > If you replace a reaction of a joint with one very strong
> > AnyGeneral muscle
> > > in each direction then the model will work almost as before but
> > now the
> > > reaction force is now part of the muscle recruitment. The
> stronger
> > this
> > > muscle is, the more this problem will act as a normal constraint
> > and the
> > > lower the strength is the more the model will “feel the cost” of
> > using this
> > > muscle and try to recruit the other muscles in a way that will
> > lower the
> > > activity of this muscle.
> > >
> > >
> > >
> > > So in this way you can not add an absolute limit to the
> constraint
> > but you
> > > can control it to some extend. Please be aware that this setup
> > requires some
> > > checking. If you want to use low strength values you should
> > carefully check
> > > the consequences of this on the model. If the strength is low
> you
> > may end up
> > > with a model where this muscle is defining the height of the
> > activity
> > > envelope, which means that the model will try in every way
> > possible to lower
> > > the activation of this “reaction”, this may not be a
> physiological
> > muscle
> > > recruitment criteria for the normal muscles.
> > >
> > >
> > >
> > > Best regards
> > >
> > > SÃ¸ren, AnyBody Support
> > >
> > >
> > >
> > > _____
> > >
> > > From: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com
> [mailto:anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com]
> > On Behalf
> > > Of rubertel
> > > Sent: 02 December 2008 03:15
> > > To: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com
> > > Subject: [AnyScript] How to constraint reaction loads
> > >
> > >
> > >
> > > Hi
> > >
> > > I am working on a simplified 2D lumbar spine model with 5
> revolute
> > > joints. I have the reactions loads set to “off” and I added
> > passive
> > > resistance to each joint. I used the AnyForceMeasure2 to
> calculate
> > my
> > > reaction loads and moment at each joint. I would like to add
> > > constraints to my reaction loads, such as minimize moment or
> > minimize
> > > shear.
> > > Can you please give me some advice on how I can constraint my
> > > reactions?
> > >
> > > Thanks,
> > >
> > > Lissette
> > >
> > >
> > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

What is the difference between having driver reactions ON and using
dummy muscles to control the driver reaction moment? Is there an
advantage to using one versus the other?
Also is it possible to have a joint with its reactions turned off
(controlled by dummy muscles) and also have the joint driver reactions
off (controlled by dummy muscles). I am getting unbounded problems.

Lissette

— In anyscript@yahoogroups.com, “rubertel” <rubertel@…> wrote:
>
> Hi Soren
>
> I was able to use the dummy muscle to control the reaction loads at
> the joints. The problem I have now is that the moment at each level
> seems to be random. It changes sign and increases and decreases from
> one level to the next. I would like to be able to make the reaction
> moment at each level a fraction of the ground reaction forces. For
> example if my reaction moment at the sacrum is 5.0Nm. Then L5
should
> be 4.0Nm, L3, 3.0Nm and so on. I tried turning the driver reactions
> off and using a passive resistance, but the software says that the
> problem is unbounded.
> Is there a way to control this reaction moment?
>
> Lissette
>
>
>
> — In anyscript@yahoogroups.com, AnyScript Support <anyscriptsup@>
> wrote:
> >
> > Hi Lissette
> >
> >
> >
> > It is actually possible to restrict the directions of the reaction
> forces to
> > be within a certain range, if they are created with the AnyGeneral
> muscles.
> >
> >
> >
> > This exactly what is done in the GH joint in the shoulder!. The GH
> joint is
> > a spherical joint, which reactions have been switched off.
Swithing
> off the
> > reaction is possible in all joints, by changing the following
> property.
> >
> >
> >
> > Constraints.Reaction.Type, by default all its components will be
on
> but you
> > can remove reactions individually from the joint.
> >
> >
> >
> > For a revolute joint settings like
> > Constraints.Reaction.Type={off,off,off,on,on}; will mean that all
> three
> > forces reactions are switched off whereas the moment reactions is
> still on.
> >
> >
> >
> > In the GH joint we wanted to constrain the direction of the
reaction
> force
> > to fall within the glenoid cavity of scapula. To ensure this,
eight
> pushing
> > muscles now acts from the gh joint rotation center onto the edge
of
> the
> > glenoid cavity, to try to picture this setup it resembles the
frame
> of a
> > tipi tent ;-).
> >
> >
> >
> > Since each of the muscles can only push there is no way that the
> resultant
> > force can fall outside the cavity of the glenoid cavity.
> >
> >
> >
> > The setup of the gh reactions can be found in the file
> > body/aauhuman/arm/ghreaction.any, this is a good example on how to
> implement
> > this.
> >
> >
> >
> > Your case is not exactly the same but it resembles a lot, in my
> imagination
> > of your problem you will have to define a number of new nodes with
> the same
> > location but different rotations, but each vector which is lying
in
> 20 deg
> > with wrt to horizontal. For each node you will create an
> AnykinLinear and a
> > pushing and pulling muscles acting on it. Then the solver will be
> able to
> > choose any combination of these vectors it can maximally be 20 deg
> because
> > there is no combination of vectors that can create forces above 20
> deg.
> > This setup limits the angle not the size of the force.
> >
> >
> >
> >
> >
> > When doing these kinds of models, it is a good idea to start
simple
> >
> > 1 do a one segment model
> >
> > 2 apply the joint
> >
> > 3 remove the constraints as needed
> >
> > 4 apply the muscles needed, to do so you will also need to add so
> new nodes
> > with are rotated with the desired angles.
> >
> > 5 evaluate the results and make sure it makes sense.
> >
> >
> >
> > I know I may sound a bit complicate, but try to look at the
> ghreaction.any
> > file it may help explain it better.
> >
> >
> >
> >
> >
> > Best regards
> >
> > SÃ¸ren, AnyBody Support
> >
> >
> >
> > _____
> >
> > From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com]
> On Behalf
> > Of rubertel
> > Sent: 11 December 2008 00:09
> > To: anyscript@yahoogroups.com
> > Subject: [AnyScript] Re: How to constraint reaction loads
> >
> >
> >
> > Hi Soren
> >
> > I also wanted to add, that my objective is to restrict the
> > orientation of the resultant reaction load not necesarrily its
> > magnitude. For example say you have a Resultant Reaction force of
> > magnitude 10 at an angle of 20deg. I would like to know what
muscle
> > loads are necesarry to restrict the resultant to act at an angle
of
> > 10deg, which is known to me. Ofcourse one is dependent of the
other,
> > by changing teh components you change the direction of teh
resultant
> > So in essence I know the direction of my resultant joint
reactions.
> > Would I still need to use the dummy muscles or could I use
someting
> > similar to the dummy segment?
> >
> > Lissette
> >
> > — In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
> ps.com,
> > “rubertel” <rubertel@> wrote:
> > >
> > > Hi Soren
> > >
> > > I am not sure how to define a dummy muscle to replace all
> > reactions.
> > > Let’s say I would usually have a revolute joint between two
> > segments.
> > > Do I still define a revolute joint? and use the comand
AnyReaction
> > > Force to link it with 5 dummy muscles.
> > > Is there an example I can look at?
> > >
> > > Lissette
> > >
> > >
> > > — In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
> ps.com,
> > AnyScript Support
> > > <anyscriptsup@> wrote:
> > > >
> > > > Hi Lisette
> > > >
> > > >
> > > >
> > > > It is not in general possible to add limits to the size of
> > > constraint in
> > > > joints.
> > > >
> > > >
> > > >
> > > > If you want the constraints to be minimized then you have to
> > > remodel these
> > > > as AnyGeneral Muscles instead, this will make them part of the
> > > recruitment
> > > > problem and they can be minimized just like any other muscle
in
> > > the model.
> > > >
> > > >
> > > >
> > > > The AnyGeneral muscles are muscles that can be applied to any
> > > measure, if
> > > > applied to a linear measure the supply force if applied to
> > > rotations they
> > > > supply moment. The muscles act in one direction you can set if
> > the
> > > muscles
> > > > should push or pull, default is pulling. This is controlled by
> > the
> > > > ForceDirection variable which default is “-1” by setting this
> > > to “1” you
> > > > have a muscle which is creating a push force.
> > > >
> > > >
> > > >
> > > > If you replace a reaction of a joint with one very strong
> > > AnyGeneral muscle
> > > > in each direction then the model will work almost as before
but
> > > now the
> > > > reaction force is now part of the muscle recruitment. The
> > stronger
> > > this
> > > > muscle is, the more this problem will act as a normal
constraint
> > > and the
> > > > lower the strength is the more the model will “feel the cost”
of
> > > using this
> > > > muscle and try to recruit the other muscles in a way that will
> > > lower the
> > > > activity of this muscle.
> > > >
> > > >
> > > >
> > > > So in this way you can not add an absolute limit to the
> > constraint
> > > but you
> > > > can control it to some extend. Please be aware that this setup
> > > requires some
> > > > checking. If you want to use low strength values you should
> > > carefully check
> > > > the consequences of this on the model. If the strength is low
> > you
> > > may end up
> > > > with a model where this muscle is defining the height of the
> > > activity
> > > > envelope, which means that the model will try in every way
> > > possible to lower
> > > > the activation of this “reaction”, this may not be a
> > physiological
> > > muscle
> > > > recruitment criteria for the normal muscles.
> > > >
> > > >
> > > >
> > > > Best regards
> > > >
> > > > SÃ¸ren, AnyBody Support
> > > >
> > > >
> > > >
> > > > _____
> > > >
> > > > From: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
> ps.com
> > [mailto:anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
> ps.com]
> > > On Behalf
> > > > Of rubertel
> > > > Sent: 02 December 2008 03:15
> > > > To: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
> ps.com
> > > > Subject: [AnyScript] How to constraint reaction loads
> > > >
> > > >
> > > >
> > > > Hi
> > > >
> > > > I am working on a simplified 2D lumbar spine model with 5
> > revolute
> > > > joints. I have the reactions loads set to “off” and I added
> > > passive
> > > > resistance to each joint. I used the AnyForceMeasure2 to
> > calculate
> > > my
> > > > reaction loads and moment at each joint. I would like to add
> > > > constraints to my reaction loads, such as minimize moment or
> > > minimize
> > > > shear.
> > > > Can you please give me some advice on how I can constraint my
> > > > reactions?
> > > >
> > > > Thanks,
> > > >
> > > > Lissette
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > [Non-text portions of this message have been removed]
> > > >
> > >
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>

Hi Lissette,

The advantage muscles are different from reactions on two points:

1. They are not infinitely strong.
2. They are unilateral.

So you can use muscles instead of reactions if you want a joint that
can only carry loads in one direction. You can also use them if you
want to force the system to recruit the muscles such that the
reaction force in the joint is limited, for instance to model the
effect of a sore joint.

The joint reactions and joint driver reactions are not related in any
other way than they are a part of the same mechanical system. So the
combination of reactions you can control with dummy muscles is only
limited by the necessity to obatin equilibrium, and this is most
likely the problem you have if you are getting unbounded problems.

This is usually caused by the fact that dummy muscle constraints are
unilateral. So the model may work for some postures and loads and
fail for others because they require reactions in a direction that
you do not have muscles for.

If you want to carry a reaction with dummy muscles and you want
reactions in both directions then you need two muscles for that
reaction, one for each direction.

Best regards,
John

— In anyscript@yahoogroups.com, “rubertel” <rubertel@…> wrote:
>
> What is the difference between having driver reactions ON and using
> dummy muscles to control the driver reaction moment? Is there an
> advantage to using one versus the other?
> Also is it possible to have a joint with its reactions turned off
> (controlled by dummy muscles) and also have the joint driver
reactions
> off (controlled by dummy muscles). I am getting unbounded problems.
>
>
> Lissette
>
>
>
> — In anyscript@yahoogroups.com, “rubertel” <rubertel@> wrote:
> >
> > Hi Soren
> >
> > I was able to use the dummy muscle to control the reaction loads
at
> > the joints. The problem I have now is that the moment at each
level
> > seems to be random. It changes sign and increases and decreases
from
> > one level to the next. I would like to be able to make the
reaction
> > moment at each level a fraction of the ground reaction forces.
For
> > example if my reaction moment at the sacrum is 5.0Nm. Then L5
> should
> > be 4.0Nm, L3, 3.0Nm and so on. I tried turning the driver
reactions
> > off and using a passive resistance, but the software says that
the
> > problem is unbounded.
> > Is there a way to control this reaction moment?
> >
> > Lissette
> >
> >
> >
> > — In anyscript@yahoogroups.com, AnyScript Support
<anyscriptsup@>
> > wrote:
> > >
> > > Hi Lissette
> > >
> > >
> > >
> > > It is actually possible to restrict the directions of the
reaction
> > forces to
> > > be within a certain range, if they are created with the
AnyGeneral
> > muscles.
> > >
> > >
> > >
> > > This exactly what is done in the GH joint in the shoulder!. The
GH
> > joint is
> > > a spherical joint, which reactions have been switched off.
> Swithing
> > off the
> > > reaction is possible in all joints, by changing the following
> > property.
> > >
> > >
> > >
> > > Constraints.Reaction.Type, by default all its components will
be
> on
> > but you
> > > can remove reactions individually from the joint.
> > >
> > >
> > >
> > > For a revolute joint settings like
> > > Constraints.Reaction.Type={off,off,off,on,on}; will mean that
all
> > three
> > > forces reactions are switched off whereas the moment reactions
is
> > still on.
> > >
> > >
> > >
> > > In the GH joint we wanted to constrain the direction of the
> reaction
> > force
> > > to fall within the glenoid cavity of scapula. To ensure this,
> eight
> > pushing
> > > muscles now acts from the gh joint rotation center onto the
edge
> of
> > the
> > > glenoid cavity, to try to picture this setup it resembles the
> frame
> > of a
> > > tipi tent ;-).
> > >
> > >
> > >
> > > Since each of the muscles can only push there is no way that
the
> > resultant
> > > force can fall outside the cavity of the glenoid cavity.
> > >
> > >
> > >
> > > The setup of the gh reactions can be found in the file
> > > body/aauhuman/arm/ghreaction.any, this is a good example on how
to
> > implement
> > > this.
> > >
> > >
> > >
> > > Your case is not exactly the same but it resembles a lot, in my
> > imagination
> > > of your problem you will have to define a number of new nodes
with
> > the same
> > > location but different rotations, but each vector which is
lying
> in
> > 20 deg
> > > with wrt to horizontal. For each node you will create an
> > AnykinLinear and a
> > > pushing and pulling muscles acting on it. Then the solver will
be
> > able to
> > > choose any combination of these vectors it can maximally be 20
deg
> > because
> > > there is no combination of vectors that can create forces above
20
> > deg.
> > > This setup limits the angle not the size of the force.
> > >
> > >
> > >
> > >
> > >
> > > When doing these kinds of models, it is a good idea to start
> simple
> > >
> > > 1 do a one segment model
> > >
> > > 2 apply the joint
> > >
> > > 3 remove the constraints as needed
> > >
> > > 4 apply the muscles needed, to do so you will also need to add
so
> > new nodes
> > > with are rotated with the desired angles.
> > >
> > > 5 evaluate the results and make sure it makes sense.
> > >
> > >
> > >
> > > I know I may sound a bit complicate, but try to look at the
> > ghreaction.any
> > > file it may help explain it better.
> > >
> > >
> > >
> > >
> > >
> > > Best regards
> > >
> > > SÃ¸ren, AnyBody Support
> > >
> > >
> > >
> > > _____
> > >
> > > From: anyscript@yahoogroups.com
[mailto:anyscript@yahoogroups.com]
> > On Behalf
> > > Of rubertel
> > > Sent: 11 December 2008 00:09
> > > To: anyscript@yahoogroups.com
> > > Subject: [AnyScript] Re: How to constraint reaction loads
> > >
> > >
> > >
> > > Hi Soren
> > >
> > > I also wanted to add, that my objective is to restrict the
> > > orientation of the resultant reaction load not necesarrily its
> > > magnitude. For example say you have a Resultant Reaction force
of
> > > magnitude 10 at an angle of 20deg. I would like to know what
> muscle
> > > loads are necesarry to restrict the resultant to act at an
angle
> of
> > > 10deg, which is known to me. Ofcourse one is dependent of the
> other,
> > > by changing teh components you change the direction of teh
> resultant
> > > So in essence I know the direction of my resultant joint
> reactions.
> > > Would I still need to use the dummy muscles or could I use
> someting
> > > similar to the dummy segment?
> > >
> > > Lissette
> > >
> > > — In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
> > ps.com,
> > > “rubertel” <rubertel@> wrote:
> > > >
> > > > Hi Soren
> > > >
> > > > I am not sure how to define a dummy muscle to replace all
> > > reactions.
> > > > Let’s say I would usually have a revolute joint between two
> > > segments.
> > > > Do I still define a revolute joint? and use the comand
> AnyReaction
> > > > Force to link it with 5 dummy muscles.
> > > > Is there an example I can look at?
> > > >
> > > > Lissette
> > > >
> > > >
> > > > — In anyscript@yahoogrou <mailto:anyscript%
40yahoogroups.com>
> > ps.com,
> > > AnyScript Support
> > > > <anyscriptsup@> wrote:
> > > > >
> > > > > Hi Lisette
> > > > >
> > > > >
> > > > >
> > > > > It is not in general possible to add limits to the size of
> > > > constraint in
> > > > > joints.
> > > > >
> > > > >
> > > > >
> > > > > If you want the constraints to be minimized then you have
to
> > > > remodel these
> > > > > as AnyGeneral Muscles instead, this will make them part of
the
> > > > recruitment
> > > > > problem and they can be minimized just like any other
muscle
> in
> > > > the model.
> > > > >
> > > > >
> > > > >
> > > > > The AnyGeneral muscles are muscles that can be applied to
any
> > > > measure, if
> > > > > applied to a linear measure the supply force if applied to
> > > > rotations they
> > > > > supply moment. The muscles act in one direction you can set
if
> > > the
> > > > muscles
> > > > > should push or pull, default is pulling. This is controlled
by
> > > the
> > > > > ForceDirection variable which default is “-1” by setting
this
> > > > to “1” you
> > > > > have a muscle which is creating a push force.
> > > > >
> > > > >
> > > > >
> > > > > If you replace a reaction of a joint with one very strong
> > > > AnyGeneral muscle
> > > > > in each direction then the model will work almost as before
> but
> > > > now the
> > > > > reaction force is now part of the muscle recruitment. The
> > > stronger
> > > > this
> > > > > muscle is, the more this problem will act as a normal
> constraint
> > > > and the
> > > > > lower the strength is the more the model will “feel the
cost”
> of
> > > > using this
> > > > > muscle and try to recruit the other muscles in a way that
will
> > > > lower the
> > > > > activity of this muscle.
> > > > >
> > > > >
> > > > >
> > > > > So in this way you can not add an absolute limit to the
> > > constraint
> > > > but you
> > > > > can control it to some extend. Please be aware that this
setup
> > > > requires some
> > > > > checking. If you want to use low strength values you should
> > > > carefully check
> > > > > the consequences of this on the model. If the strength is
low
> > > you
> > > > may end up
> > > > > with a model where this muscle is defining the height of
the
> > > > activity
> > > > > envelope, which means that the model will try in every way
> > > > possible to lower
> > > > > the activation of this “reaction”, this may not be a
> > > physiological
> > > > muscle
> > > > > recruitment criteria for the normal muscles.
> > > > >
> > > > >
> > > > >
> > > > > Best regards
> > > > >
> > > > > SÃ¸ren, AnyBody Support
> > > > >
> > > > >
> > > > >
> > > > > _____
> > > > >
> > > > > From: anyscript@yahoogrou <mailto:anyscript%
40yahoogroups.com>
> > ps.com
> > > [mailto:anyscript@yahoogrou <mailto:anyscript%
40yahoogroups.com>
> > ps.com]
> > > > On Behalf
> > > > > Of rubertel
> > > > > Sent: 02 December 2008 03:15
> > > > > To: anyscript@yahoogrou <mailto:anyscript%
40yahoogroups.com>
> > ps.com
> > > > > Subject: [AnyScript] How to constraint reaction loads
> > > > >
> > > > >
> > > > >
> > > > > Hi
> > > > >
> > > > > I am working on a simplified 2D lumbar spine model with 5
> > > revolute
> > > > > joints. I have the reactions loads set to “off” and I added
> > > > passive
> > > > > resistance to each joint. I used the AnyForceMeasure2 to
> > > calculate
> > > > my
> > > > > reaction loads and moment at each joint. I would like to
> > > > > constraints to my reaction loads, such as minimize moment
or
> > > > minimize
> > > > > shear.
> > > > > Can you please give me some advice on how I can constraint
my
> > > > > reactions?
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Lissette
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > [Non-text portions of this message have been removed]
> > > > >
> > > >
> > >
> > >
> > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >
>

Hi Lissette

If you have no muscles in the model and you switch off the reaction in the
joints and replace these by passive forces then it is sounds very plausible
that the model will not be able to solve the inverse dyn. analysis. To make
this approach work it would mean that the passive forces should balance out
exactly the applied load, this will almost never be case. It is important to
remember that this is inverse dyn. the motion is input and the motion will
define the passive resistance in the joints. So to create the balance you
would need to supply the motion that exactly create passive resistance that

The question about the reaction moments: I think it can be implemented but
I can not see the physiological motivation for it?

The approach would be to use one muscle for all these reaction, and then use
a AnyKinLinearCombMeasure to supply the force from these muscles in terms of
ground reaction force, L5 moment, l4 moment and so on. The coefficients in
the measure will determine how the force would be divided, these
coefficients should also account for the mix between forces and moments.

Best regards

SÃ¸ren, AnyBody Support

From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com] On Behalf
Of rubertel
Sent: 19 January 2009 21:42
To: anyscript@yahoogroups.com
Subject: [AnyScript] Re: How to constraint reaction loads

Hi Soren

I was able to use the dummy muscle to control the reaction loads at
the joints. The problem I have now is that the moment at each level
seems to be random. It changes sign and increases and decreases from
one level to the next. I would like to be able to make the reaction
moment at each level a fraction of the ground reaction forces. For
example if my reaction moment at the sacrum is 5.0Nm. Then L5 should
be 4.0Nm, L3, 3.0Nm and so on. I tried turning the driver reactions
off and using a passive resistance, but the software says that the
problem is unbounded.
Is there a way to control this reaction moment?

Lissette

— In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com,
AnyScript Support <anyscriptsup@…>
wrote:
>
> Hi Lissette
>
>
>
> It is actually possible to restrict the directions of the reaction
forces to
> be within a certain range, if they are created with the AnyGeneral
muscles.
>
>
>
> This exactly what is done in the GH joint in the shoulder!. The GH
joint is
> a spherical joint, which reactions have been switched off. Swithing
off the
> reaction is possible in all joints, by changing the following
property.
>
>
>
> Constraints.Reaction.Type, by default all its components will be on
but you
> can remove reactions individually from the joint.
>
>
>
> For a revolute joint settings like
> Constraints.Reaction.Type={off,off,off,on,on}; will mean that all
three
> forces reactions are switched off whereas the moment reactions is
still on.
>
>
>
> In the GH joint we wanted to constrain the direction of the reaction
force
> to fall within the glenoid cavity of scapula. To ensure this, eight
pushing
> muscles now acts from the gh joint rotation center onto the edge of
the
> glenoid cavity, to try to picture this setup it resembles the frame
of a
> tipi tent ;-).
>
>
>
> Since each of the muscles can only push there is no way that the
resultant
> force can fall outside the cavity of the glenoid cavity.
>
>
>
> The setup of the gh reactions can be found in the file
> body/aauhuman/arm/ghreaction.any, this is a good example on how to
implement
> this.
>
>
>
> Your case is not exactly the same but it resembles a lot, in my
imagination
> of your problem you will have to define a number of new nodes with
the same
> location but different rotations, but each vector which is lying in
20 deg
> with wrt to horizontal. For each node you will create an
AnykinLinear and a
> pushing and pulling muscles acting on it. Then the solver will be
able to
> choose any combination of these vectors it can maximally be 20 deg
because
> there is no combination of vectors that can create forces above 20
deg.
> This setup limits the angle not the size of the force.
>
>
>
>
>
> When doing these kinds of models, it is a good idea to start simple
>
> 1 do a one segment model
>
> 2 apply the joint
>
> 3 remove the constraints as needed
>
> 4 apply the muscles needed, to do so you will also need to add so
new nodes
> with are rotated with the desired angles.
>
> 5 evaluate the results and make sure it makes sense.
>
>
>
> I know I may sound a bit complicate, but try to look at the
ghreaction.any
> file it may help explain it better.
>
>
>
>
>
> Best regards
>
> SÃ¸ren, AnyBody Support
>
>
>
> _____
>
> From: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com
[mailto:anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com]
On Behalf
> Of rubertel
> Sent: 11 December 2008 00:09
> To: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com
> Subject: [AnyScript] Re: How to constraint reaction loads
>
>
>
> Hi Soren
>
> I also wanted to add, that my objective is to restrict the
> orientation of the resultant reaction load not necesarrily its
> magnitude. For example say you have a Resultant Reaction force of
> magnitude 10 at an angle of 20deg. I would like to know what muscle
> loads are necesarry to restrict the resultant to act at an angle of
> 10deg, which is known to me. Ofcourse one is dependent of the other,
> by changing teh components you change the direction of teh resultant
> So in essence I know the direction of my resultant joint reactions.
> Would I still need to use the dummy muscles or could I use someting
> similar to the dummy segment?
>
> Lissette
>
> — In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com,
> “rubertel” <rubertel@> wrote:
> >
> > Hi Soren
> >
> > I am not sure how to define a dummy muscle to replace all
> reactions.
> > Let’s say I would usually have a revolute joint between two
> segments.
> > Do I still define a revolute joint? and use the comand AnyReaction
> > Force to link it with 5 dummy muscles.
> > Is there an example I can look at?
> >
> > Lissette
> >
> >
> > — In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com,
> AnyScript Support
> > <anyscriptsup@> wrote:
> > >
> > > Hi Lisette
> > >
> > >
> > >
> > > It is not in general possible to add limits to the size of
> > constraint in
> > > joints.
> > >
> > >
> > >
> > > If you want the constraints to be minimized then you have to
> > remodel these
> > > as AnyGeneral Muscles instead, this will make them part of the
> > recruitment
> > > problem and they can be minimized just like any other muscle in
> > the model.
> > >
> > >
> > >
> > > The AnyGeneral muscles are muscles that can be applied to any
> > measure, if
> > > applied to a linear measure the supply force if applied to
> > rotations they
> > > supply moment. The muscles act in one direction you can set if
> the
> > muscles
> > > should push or pull, default is pulling. This is controlled by
> the
> > > ForceDirection variable which default is “-1” by setting this
> > to “1” you
> > > have a muscle which is creating a push force.
> > >
> > >
> > >
> > > If you replace a reaction of a joint with one very strong
> > AnyGeneral muscle
> > > in each direction then the model will work almost as before but
> > now the
> > > reaction force is now part of the muscle recruitment. The
> stronger
> > this
> > > muscle is, the more this problem will act as a normal constraint
> > and the
> > > lower the strength is the more the model will “feel the cost” of
> > using this
> > > muscle and try to recruit the other muscles in a way that will
> > lower the
> > > activity of this muscle.
> > >
> > >
> > >
> > > So in this way you can not add an absolute limit to the
> constraint
> > but you
> > > can control it to some extend. Please be aware that this setup
> > requires some
> > > checking. If you want to use low strength values you should
> > carefully check
> > > the consequences of this on the model. If the strength is low
> you
> > may end up
> > > with a model where this muscle is defining the height of the
> > activity
> > > envelope, which means that the model will try in every way
> > possible to lower
> > > the activation of this “reaction”, this may not be a
> physiological
> > muscle
> > > recruitment criteria for the normal muscles.
> > >
> > >
> > >
> > > Best regards
> > >
> > > SÃ¸ren, AnyBody Support
> > >
> > >
> > >
> > > _____
> > >
> > > From: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com
> [mailto:anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com]
> > On Behalf
> > > Of rubertel
> > > Sent: 02 December 2008 03:15
> > > To: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com
> > > Subject: [AnyScript] How to constraint reaction loads
> > >
> > >
> > >
> > > Hi
> > >
> > > I am working on a simplified 2D lumbar spine model with 5
> revolute
> > > joints. I have the reactions loads set to “off” and I added
> > passive
> > > resistance to each joint. I used the AnyForceMeasure2 to
> calculate
> > my
> > > reaction loads and moment at each joint. I would like to add
> > > constraints to my reaction loads, such as minimize moment or
> > minimize
> > > shear.
> > > Can you please give me some advice on how I can constraint my
> > > reactions?
> > >
> > > Thanks,
> > >
> > > Lissette
> > >
> > >
> > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

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