Hi Javed,
For the referring of the dof you are right, I wrote it in the wrong
order last time. I’m sorry about that. I think I was focused on the
sequence defined in the driver that is not the same as the real
sequence of the axis in the joint. The right references are dof0 /
lateral bending, dof1 / axial rotation and dof2 / extension.
Now regarding to the activity without gravity, I have just run the
standing model (without muscles and without gravity) and I do see a
moment on the lumbar joints. Of course the moment is small but it is
there. Here are the values I have for 30 degrees of flexion in the
negative muscle of L5Sacrum.
XY
Main.Study.Output.Model.HumanModel.Trunk.JointMuscles.L5Sacrum
Jnt.dof2.Muscle.NegMuscle.Fm
0,00 0,00e+000
0,11 0,00e+000
0,22 0,00e+000
0,33 0,00e+000
0,44 6,88e-002
0,56 2,72e-001
0,67 4,75e-001
0,78 6,77e-001
0,89 8,77e-001
1,00 1,07e+000
By “good muscle” I mean the appropriate muscle, in this case the
negative muscle for dof2. Please look for this same output after
performing a flexion. You should not found zero moment.
Best regards,
Sylvain, AnyBody Support.
— In anyscript@yahoogroups.com, “javed377” <javed377@…> wrote:
>
> Hello Sylvian,
>
> I am sorry…for asking again and again.
> Actually you are so detailed, but your information that dof0 refers
to
> extension, dof1 to lateral bending and dof2 to rotation surprises
me.
> I found a moment in dof2 for extension (resp. flexion). This seems
> logical as z faces to the right side of the body. Did i understand
> something wrongly?
>
> You said “Even without gravity there is a moment to move the body”.
> That is not what i found! (Pleas remember that i use the model
without
> muscles) I found zero moment for zero gravity 
(for dof0, dof1,
and
> dof2, negativ as well as positive).
> What do you mean with “good muscle”?
>
> It is absolutely not clear for me, why the moment is zero at zero
> gravity. Could you please give me a clue?
>
> Thanks, Javed
>
>
>
> — In anyscript@yahoogroups.com, “AnyBody Support” <support@>
wrote:
> >
> >
> > Hi Javed,
> >
> > The path I gave you is for repository 7. If you use the
repository 6
> > the path is a little different:
> >
Main.Study.Output.Model.HumanModel.Trunk.JointMuscles.L1L2Jnt.dof0.Mus
> > cle.PosMuscle.Fm
> > As you noticed instead of Extension or LateralBending or Rotation
you
> > have to pick directly dof0 or dof1 or dof2. The dof corresponding
to
> > extension is dof0 (dof1 for lateral bending and dof2 for
rotation).
> >
> > Even without gravity there is a moment to move the body as you
said
> > it. You can see it if you look at the good muscle. If you perform
an
> > extension you will that the positive muscle of dof0 is active. If
you
> > perform a flexion then it will be the negative muscle of dof0
that
> > will be active.
> >
> > Best regards,
> > Sylvain, AnyBody Support.
> >
> >
> >
> >
> >
> > — In anyscript@yahoogroups.com, “javed377” <javed377@> wrote:
> > >
> > > Hello Sylvian,
> > >
> > > Many thanks for your replies. I need more to know that
> > >
> > >
> >
Main.Study.Output.Model.HumanModel.Trunk.JointMuscles.L1L2Jnt.Extensio
> > > n.dof0.Muscle.PosMuscle.Fm
> > > does not exist in my model. Without “Extension” it exists. Have
you
> > > got repository ver. 7?
> > >
> > > For flexion, i think DOF 2 is relevant?
> > >
> > > I don’t understand the following: Why is the Fm proportional to
the
> > > gravity (always without muscles)? When there is physical no
> > gravity, a
> > > moment should nevertheless be necessary to deform the
structure.
> > When
> > > i run the model with a zero gravity, zero moment comes out.
> > >
> > > Have you got some hints, please?
> > >
> > > Thanks,
> > >
> > > Javed
> > > >
> > > >
> > > > Hi Javed,
> > > >
> > > > You can visualize the force of the artificial torque in the
> > chartFX
> > > > windows. More exactly those torque are created with
> > > > AnyGeneralMuscles, they are not real muscles and are acting
> > exactly
> > > > like a pure moment applied to the joint.
> > > > Please find in the chartFX windows:
> > > >
> >
Main.Study.Output.Model.HumanModel.Trunk.JointMuscles.L1L2Jnt.Extensio
> > > > n.dof0.Muscle.PosMuscle.Fm
> > > > This is for example the torque acting for the positive thorax
> > flexion
> > > > in T12L1 joint.
> > > >
> > > > Best regards,
> > > > Sylvain, AnyBody Support.
> > > >
> > > >
> > > >
> > > >
> > > > — In anyscript@yahoogroups.com, “javed377” <javed377@>
wrote:
> > > > >
> > > > > Hi Sylvain,
> > > > >
> > > > > Thanks for you nice response. But still one thing is not
clear
> > to me
> > > > > how to find the artificial torque?
> > > > >
> > > > > With best regards.
> > > > >
> > > > > Javed
> > > > >
> > > > >
> > > > > — In anyscript@yahoogroups.com, “AnyBody Support”
<support@>
> > > > wrote:
> > > > > >
> > > > > > Hi Javed,
> > > > > >
> > > > > > Sorry I was looking at the model with muscles. But yes
you
> > are
> > > > right,
> > > > > > the reaction forces in T12L1 and L5Sacrum (and the others
> > lumbar
> > > > > > joints) does not change during flexion when using the
model
> > > > without
> > > > > > muscles. And the reason is precisely because there are no
> > muscles
> > > > in
> > > > > > the model:
> > > > > > In the NoMuscle body model the forces acting on a segment
are
> > the
> > > > > > gravity, the joint reaction forces and the artificial
torque
> > in
> > > > the
> > > > > > joint. The artificial torque replaces the muscles. So in
this
> > > > case
> > > > > > the reaction force of the joint Fout is only acting
against
> > the
> > > > > > weight of the segments (the moments are carried by the
torque
> > and
> > > > > > does not appear in Fout). And in global coordinates the
> > weight is
> > > > > > always constant along the Y axis. That is why you can see
> > that
> > > > the
> > > > > > reaction force of T12l1 in global coordinates doesn’t
change.
> > > > > >
> > > > > > I hope this makes it clear.
> > > > > >
> > > > > > Best regards,
> > > > > > Sylvain, AnyBody Support.
> > > > > >
> > > > > >
> > > > > >
> > > > > > — In anyscript@yahoogroups.com, “javed377” <javed377@>
> > wrote:
> > > > > > >
> > > > > > > Hi Sylvain,
> > > > > > >
> > > > > > > Thanks for your qucik response. I let a colleague of
mine
> > check
> > > > my
> > > > > > > findings. He found the same: For the standing model
> > > > (Repository6.1)
> > > > > > > without muscles (the original StandingModel.Main.any
but
> > > > without the
> > > > > > > 10 N at the right hand) we did 3 separate kinematic
> > analyses
> > > > and
> > > > > > found
> > > > > > > the following local forces at T12L1 and L5Sacrum.Incase
of
> > > > model
> > > > > > with
> > > > > > > muscles you are right that forces do change, but please
> > take a
> > > > look
> > > > > > in
> > > > > > > case of StandingModel without muslces.
> > > > > > >
> > > > > > > 0 degree PelvisThoraxExtension:
> > > > > > > T12L1 Reaction.Fout: {10.4; 311; 0} Axes
[0][0]
> > > > =0.999
> > > > > > > L5Sacrum: Reaction.Fout: {13.8; 414; 0} Axes[0][0]
> > =0.999
> > > > > > >
> > > > > > > -50 degrees:
> > > > > > > T12L1: Reaction.Fout {-159; 268; 0} Axes
> > [0][0]
> > > > > > =0.859
> > > > > > > L5Sacrum: Reaction.Fout {41; 412;0} Axes[0][0]
> > =0.995
> > > > > > >
> > > > > > > -90 degrees:
> > > > > > > T12L1: Reaction.Fout {-265; 164; 0} Axes
> > [0][0]
> > > > > > =0.526
> > > > > > > L5Sacrum: Reaction.Fout {52; 411; 0} Axes[0][0]
> > =0.992
> > > > > > >
> > > > > > > Transforming the joint forces to the global system
results
> > in
> > > > {0;
> > > > > > 311;
> > > > > > > 0} and {0; 414; 0} for ALL three flexion angles. Have
you
> > got
> > > > an
> > > > > > idea
> > > > > > > how to interpret these results?
> > > > > > >
> > > > > > > Thanks,
> > > > > > >
> > > > > > > Javed
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > — In anyscript@yahoogroups.com, “AnyBody Support”
> > <support@>
> > > > > > wrote:
> > > > > > > >
> > > > > > > > Hi Javed,
> > > > > > > >
> > > > > > > > Your question is quite surprising because the
reaction
> > force
> > > > > > inT12L1
> > > > > > > > joint does change during flexion, both in global and
> > local
> > > > > > coordinate
> > > > > > > > system. So it sounds very strange when you tell me
that
> > the
> > > > > > reaction
> > > > > > > > force is not depending on flexion angle.
> > > > > > > > You said you made several static analyses, you will
not
> > be
> > > > able
> > > > > > to
> > > > > > > > see the force changing during a static analysis. You
have
> > to
> > > > > > compare
> > > > > > > > it with other static analyses with different postures.
> > > > > > > >
> > > > > > > > The forces acting on a static free body diagram are
the
> > joint
> > > > > > forces,
> > > > > > > > muscles forces and weight. As you run the model with
no
> > > > muscle
> > > > > > the
> > > > > > > > muscle forces are replaced by artificial torques in
the
> > > > joints.
> > > > > > Then
> > > > > > > > it is normal that the reaction forces are different
in
> > T12L1
> > > > and
> > > > > > > > L5Sacrum because T12L1 joint support the weight of
the
> > thorax
> > > > > > whereas
> > > > > > > > L5Sacrum joint support the lumbar segments weight in
> > addition
> > > > to
> > > > > > the
> > > > > > > > thorax. You can see the mass of a segment from the
model
> > tree
> > > > or
> > > > > > you
> > > > > > > > can measure it (one segment or a group of segment)
using
> > the
> > > > > > > > AnyForceMomentMeasure2.
> > > > > > > >
> > > > > > > > Best regards,
> > > > > > > > Sylvain, AnyBody Support.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > — In anyscript@yahoogroups.com, “javed377”
<javed377@>
> > > > wrote:
> > > > > > > > >
> > > > > > > > > Dear AnyBody team,
> > > > > > > > >
> > > > > > > > > i did some static analyses with the standing model
> > without
> > > > > > muscles
> > > > > > > > > with different thorax-pelvis flexion angles and
found
> > > > something
> > > > > > > > strange:
> > > > > > > > >
> > > > > > > > > the resultant forces on the T12L1 and the L5Sacrum
> > joint
> > > > are not
> > > > > > > > > dependent on the flexion angle?! Shouldn’t the
> > resultant
> > > > forces
> > > > > > > > > increase with increasing flexion angle? Even the
> > components
> > > > in
> > > > > > the
> > > > > > > > > global system don’t change. (Though the forces in
the
> > local
> > > > > > systems
> > > > > > > > > change.)
> > > > > > > > >
> > > > > > > > > And another question: I want to find ALL loads
acting
> > on
> > > > the
> > > > > > lumbar
> > > > > > > > > spine for a free body diagram (L1 to L5). Are there
> > other
> > > > > > forces
> > > > > > > > than
> > > > > > > > > the joint forces? (In a first step i disregard the
> > muscle
> > > > > > forces as
> > > > > > > > i
> > > > > > > > > used the model without muscles.) I wonder why the
> > resultant
> > > > > > forces
> > > > > > > > at
> > > > > > > > > T12L1 are different to L5Sacrum. Is this due to the
> > lumbar
> > > > > > mass? How
> > > > > > > > > to obtain mass forces?
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > >
> > > > > > > > > javed
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>