Hi Shashank,
- If i use AnyMan to change segment lengths with uniform
scaling
does the ligament lengths automatically get adjusted or do i have to
run a calibration study.
Actually there are no ligaments in this model, but if there where
some then yes you should run a calibration study each time you load
the model (no matter if you scale it or not, you have to run it
anyway). It is also the case for the MuscleModel_3E: if you use it
you must run the calibration study each time you load the model. But
you are now using the simple muscle model so it is not necessary to
run a calibration study.
- What is the purpose of the tolerance error. How does it
affect the
function of the model.
I suppose you are talking about the kinematics tolerance, it is the
tolerance of matching of the joints. When you get an error message
saying “kinematics error above tolerance…” that mean some joints
cannot match with enough accuracy. It is possible to change this
tolerance but it is definitely not a good idea because then your
model loose accuracy and you will get noise in the results.
- If i want to make specific muscles (eg triceps) have low
strength
or For ex a wheelchair users with C7 level injury does not have
control of abdominal musculature what is the best way to represent it
in the model.
Each muscle have is own muscle model located in BRep in the file
Muscle_Parameters, so if you want a specific muscle to be weaker or
stronger you can change the parameters in his own muscle model. In
AnyBody the strength of the muscles is calculated with the PCSA, this
is the value you have to modify.
For the case of the C7 level injury I am not sure of the exact
physical consequences on the person you want to add in the model.
Does that mean the person is not able to move the lumbar spine? In
that case you should begin by constrain the movement of the spine
with drivers. You should also think about whatever the person need to
be strapped to the seat or some other things. I guess that also mean
the person cannot contract his muscles and those muscles remain
without any activity, you could represent that behaviour by setting a
very low strength to those particular muscles, you can’t totally
remove them because the model won’t be balanced anymore.
Best regards,
Sylvain, AnyBody Support
— In anyscript@yahoogroups.com, “shashu_23” <shashankraina@…>
wrote:
>
> Hi Sylvain,
> I have a few more generic questions.
>
> 1. If i use AnyMan to change segment lengths with uniform scaling
> does the ligament lengths automatically get adjusted or do i have
to
> run a calibration study.
>
> 2. What is the purpose of the tolerance error. How does it affect
the
> function of the model.
>
> 3. If i want to make specific muscles (eg triceps) have low
strength
> or For ex a wheelchair users with C7 level injury does not have
> control of abdominal musculature what is the best way to represent
it
> in the model.
>
> Thanks
>
> Shashank
>
> — In anyscript@yahoogroups.com, “AnyBody Support” <support@>
> wrote:
> >
> > Hi Shashank,
> >
> > One of the causes of the difference of activity of the scapular
> > muscles can be the shoulder external rotation driver, precisely
the
> > one I couldn’t replace by a marker driver. That mean the shoulder
> > external rotation is fixed instead of following the marker
> movement.
> > The difference in the motion is not big and as you saw the model
is
> > running, but still that small difference will induce somehow a
> change
> > in some muscles activity (most probably in the shoulder/scapula
> > area). That’s why it would be good to have that DOF driven by the
> > marker.
> >
> > It seems your understanding of the simple driver is not correct,
> > things are like this: when you drive a joint with a simple driver
> the
> > muscles are involved in the inverse dynamics analysis as well as
if
> > you drive it with a marker. There is a parameter in the Driver
> class
> > that controls if the muscles will be active or not, it is the
> > ReactionType. If ReactionType is “Off” then muscles are normally
> > caring the load for that joint, if switched “On” the load in the
> join
> > won’t be carried by the muscles but by artificial forces
generated
> in
> > the joint. Default value of ReactionType is “Off”.
> > So clearly the difference between those two types of driver is
that
> > you cannot drive such complex motion with a simple driver than
with
> a
> > marker driver. And it affects your model in the way I explained
> > before.
> >
> > Best regards,
> > Sylvain, AnyBody Support
> >
> >
> >
> >
> >
> > — In anyscript@yahoogroups.com, “shashu_23” <shashankraina@>
> > wrote:
> > >
> > > Sylvain,
> > > I ran the model and it works fine.
> > > I also noticed that the scapular muscles are also active (this
> was
> > > not the case with Rancho model). I will look in and see how
drove
> > the
> > > scapula motion.
> > >
> > > My question is when we drive something with a simple driver.
That
> > > means the muscles for that joint won’t get involved in the
> inverse
> > > dynamics (am i correct). Could you tell me if it affects any
> other
> > > results of the model.
> > >
> > > Thanks a lot,
> > >
> > > Shashank
> > >
> > >
> > > — In anyscript@yahoogroups.com, “AnyBody Support” <support@>
> > > wrote:
> > > >
> > > > Hi,
> > > >
> > > > I think one problem comes from the initial position, some
> > segments
> > > > was not close enough to the marker. So I modified some values
> in
> > > the
> > > > mannequin file. I also changed some of the drivers for the
> trunk
> > > that
> > > > was giving me troubles: I fixed the pelvis to the ground and
I
> > > drive
> > > > 2 rotations of the thoracic spine with marker while the third
> one
> > > > keeps giving troubles and I had to drive it with a simple
> driver.
> > > > I have the model running now but there is a second driver (in
> > plus
> > > of
> > > > the trunk rotation) that I could not replace by a marker.
It’s
> > the
> > > > one for the shoulder external rotation. So far I haven’t find
> > what
> > > > cause the error for this driver, it might be a problem of
> initial
> > > > position again.
> > > > I will keep digging the problem. I uploaded the running model
> > > > (wheel_shank2).
> > > >
> > > > Best regards,
> > > > Sylvain, AnyBody Support
> > > >
> > > >
> > > > — In anyscript@yahoogroups.com, “shashu_23”
<shashankraina@>
> > > > wrote:
> > > > >
> > > > > Hi,
> > > > > I was trying to run a wheelchair model using the
template
> > > given
> > > > in
> > > > > WheelChairRancho. I was trying to keep it simple so i just
> > tried
> > > to
> > > > > replace the marker data and kept the forces the same.
> > > > > Here is what is did.
> > > > >
> > > > > 1. The motion markers i have are the same as the ones in
the
> > > model
> > > > so
> > > > > that step is fine.
> > > > >
> > > > > 2. I aligned the segments so they are close to the markers
in
> > the
> > > > > starting position.
> > > > >
> > > > > 3. The model loads up fine. The problem is when i start
> > removing
> > > > the
> > > > > drivers from the joint and drivers file. I get errors in
> right
> > > away
> > > > > and i have tried different combinations but it still keeps
> > > failing.
> > > > >
> > > > > 4. I was hoping if someone could look at the model and help
> me
> > > > figure
> > > > > out the problem with the drivers. I have uploaded the
folder
> > > called
> > > > > wheel_shank with the model in it. I have also put in the
c3d
> > > data
> > > > > file if you want it. (as i mentioned before i am still
using
> > the
> > > > > forces from the rancho file as there is some vector length
> > issues
> > > > > with the forces)
> > > > >
> > > > > It would be of great help is someone could help me figure
out
> > how
> > > > to
> > > > > solve this problem
> > > > >
> > > > > Thanks
> > > > > Shashank
> > > > >
> > > >
> > >
> >
>