Hi,
Sorry for the delay, but I just now have uploaded the simple arm model
that I had written about last week.
Thanks for all your help with this.
Sarah
Hi Sarah
I have just tried your SimpelArm model, but i have problems making
it fail the muscle recruitment as you describe. I have tried two
version of AnyBody 1.3.1 and 2.0, both of them without problems. I
have also tried to add in the outcommented muscles and some motion
to the elbow it all worked. Please let us know which version of
AnyBody you are using?, this can be seen by clicking “Help” in the
menu and then “About”. This will help us solve the problem.
Best regards
AnyBody Support
— In anyscript@yahoogroups.com, “Sarah R. Sullivan”
<sarsulli@e…>
wrote:
> Hi,
>
> Sorry for the delay, but I just now have uploaded the simple arm
model
> that I had written about last week.
>
> Thanks for all your help with this.
>
> Sarah
Hi,
The model failed the inverse dynamics analysis when I only included 1
muscle in the analysis. For example, if I only included the brachialis
and nothing else, the muscle recruitment analysis failed. I was using the
demo version of AnyBody 2.0. I also had this same problem with a couple
of two-muscle contribution combinations (such as an analysis with the
biceps short and brachialis). And lastly, when running a successful
model, with multiple muscle scenarios, I was not getting any shoulder
reaction.
I hope this helps with troubleshooting! Let me know if this doesn’t
answer any questions and I will try to troubleshoot a little here as well.
Thanks,
Sarah
> Hi Sarah
>
> I have just tried your SimpelArm model, but i have problems making
> it fail the muscle recruitment as you describe. I have tried two
> version of AnyBody 1.3.1 and 2.0, both of them without problems. I
> have also tried to add in the outcommented muscles and some motion
> to the elbow it all worked. Please let us know which version of
> AnyBody you are using?, this can be seen by clicking “Help” in
> the
> menu and then “About”. This will help us solve the problem.
>
> Best regards
> AnyBody Support
>
>
> — In anyscript@yahoogroups.com, “Sarah R. Sullivan”
>
> wrote:
> > Hi,
> >
> > Sorry for the delay, but I just now have uploaded the simple arm
> model
> > that I had written about last week.
> >
> > Thanks for all your help with this.
> >
> > Sarah
>
>
>
>
> AnyBody Technology provides free support on the use of the AnyBody
> Modeling System and the Scripting language AnyScript. Other users are
> welcome to join the discussions.
>
>
> YAHOO! GROUPS LINKS
> Visit your group “anyscript” on the web.
> To unsubscribe from this group, send an email to:
> anyscript-unsubscribe@yahoogroups.com
> Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
>
–
Sarah R. Sullivan
PhD Candidate, Biomedical Engineering
Rutgers, The State University of New Jersey
Piscataway, NJ 08854
sarsulli@eden.rutgers.edu
908-420-3371
Hi Sarah,
In that case the explanation is quite straight forward: The arm model
has two revolute joints and hence two degrees of freedom. This means
that there is no way to balance it with only one muscle. You need at
least two independent muscles when you have two degrees of freedom.
Brachialis and Biceps Short both span the elbow joint, so if you only
have those two muscles in the model, then you have nothing to balance
the shoulder joint.
The problem with the lacking shoulder reaction still remains to be
solved. When we run the model you have uploaded, we do indeed get
shoulder reaction forces. Should this problem be present in the
uploaded model, and if not could you upload a model that exhibits the
problem?
Thanks,
AnyBody Support
— In anyscript@yahoogroups.com, “Sarah R. Sullivan” <sarsulli@e…>
wrote:
> Hi,
>
> The model failed the inverse dynamics analysis when I only included
1
> muscle in the analysis. For example, if I only included the
brachialis
> and nothing else, the muscle recruitment analysis failed. I was
using the
> demo version of AnyBody 2.0. I also had this same problem with a
couple
> of two-muscle contribution combinations (such as an analysis with
the
> biceps short and brachialis). And lastly, when running a successful
> model, with multiple muscle scenarios, I was not getting any
shoulder
> reaction.
>
> I hope this helps with troubleshooting! Let me know if this doesn’t
> answer any questions and I will try to troubleshoot a little here
as well.
>
> Thanks,
> Sarah
>
> > Hi Sarah
> >
> > I have just tried your SimpelArm model, but i have problems
making
> > it fail the muscle recruitment as you describe. I have tried two
> > version of AnyBody 1.3.1 and 2.0, both of them without problems.
I
> > have also tried to add in the outcommented muscles and some
motion
> > to the elbow it all worked. Please let us know which version of
> > AnyBody you are using?, this can be seen by clicking
“Help” in
> > the
> > menu and then “About”. This will help us solve the
problem.
> >
> > Best regards
> > AnyBody Support
> >
> >
> > — In anyscript@yahoogroups.com, “Sarah R. Sullivan”
> >
> > wrote:
> > > Hi,
> > >
> > > Sorry for the delay, but I just now have uploaded the simple
arm
> > model
> > > that I had written about last week.
> > >
> > > Thanks for all your help with this.
> > >
> > > Sarah
> >
> >
> >
> >
> > AnyBody Technology provides free support on the use of the
AnyBody
> > Modeling System and the Scripting language AnyScript. Other users
are
> > welcome to join the discussions.
> >
> >
> > YAHOO! GROUPS LINKS
> > Visit your group “anyscript” on the web.
> > To unsubscribe from this group, send an email to:
> > anyscript-unsubscribe@yahoogroups.com
> > Your use of Yahoo! Groups is subject to the Yahoo! Terms of
Service.
> >
>
>
> –
> Sarah R. Sullivan
> PhD Candidate, Biomedical Engineering
> Rutgers, The State University of New Jersey
> Piscataway, NJ 08854
> sarsulli@e…
> 908-420-3371
Thanks for the quick reply. A couple of quick questions. Regarding the
arm model with two revolute joints - I will still need two muscles to run
the situation even if I have set the joint to be in one position, with no
velocity? Isn’t that fixing the degrees of freedom? Or not totally?
And also, can you give me a quick result of the shoulder forces you are
getting? I did the math myself to get something along the lines of
Fx=-440 and Fy = -~730 (off the top of my head). When I did it out by
hand, the shoulder reaction forces never changed when I varied the number
of muscles (or those involved) in the model. I’m not sure why I was
getting zero for both Fx and Fy, but I wasn’t getting any values. I’ll
have to take a look at it again.
And also, on another note, can AnyBody handle a model being driven by
different sampling rates? For example, if I drive the kinematics with
60Hz data, and the kinetics with 240Hz data, will I have to upsample or
downsample to get the model to run? Will I need to set the time step to
one of those two values, and then change the other data?
Thanks again for your time,
Sarah
> Hi Sarah,
>
> In that case the explanation is quite straight forward: The arm model
> has two revolute joints and hence two degrees of freedom. This means
> that there is no way to balance it with only one muscle. You need at
> least two independent muscles when you have two degrees of freedom.
>
> Brachialis and Biceps Short both span the elbow joint, so if you only
> have those two muscles in the model, then you have nothing to balance
> the shoulder joint.
>
> The problem with the lacking shoulder reaction still remains to be
> solved. When we run the model you have uploaded, we do indeed get
> shoulder reaction forces. Should this problem be present in the
> uploaded model, and if not could you upload a model that exhibits the
> problem?
>
> Thanks,
> AnyBody Support
>
>
> — In anyscript@yahoogroups.com, “Sarah R. Sullivan”
> wrote:
> > Hi,
> >
> > The model failed the inverse dynamics analysis when I only included
> 1
> > muscle in the analysis. For example, if I only included the
> brachialis
> > and nothing else, the muscle recruitment analysis failed. I was
> using the
> > demo version of AnyBody 2.0. I also had this same problem with a
> couple
> > of two-muscle contribution combinations (such as an analysis with
> the
> > biceps short and brachialis). And lastly, when running a successful
> > model, with multiple muscle scenarios, I was not getting any
> shoulder
> > reaction.
> >
> > I hope this helps with troubleshooting! Let me know if this doesn’t
> > answer any questions and I will try to troubleshoot a little here
> as well.
> >
> > Thanks,
> > Sarah
> >
> > > Hi Sarah
> > >
> > > I have just tried your SimpelArm model, but i have problems
> making
> > > it fail the muscle recruitment as you describe. I have tried two
> > > version of AnyBody 1.3.1 and 2.0, both of them without problems.
> I
> > > have also tried to add in the outcommented muscles and some
> motion
> > > to the elbow it all worked. Please let us know which version of
> > > AnyBody you are using?, this can be seen by clicking
> “Help” in
> > > the
> > > menu and then “About”. This will help us solve the
> problem.
> > >
> > > Best regards
> > > AnyBody Support
> > >
> > >
> > > — In anyscript@yahoogroups.com, “Sarah R.
> Sullivan”
> > >
> > > wrote:
> > > > Hi,
> > > >
> > > > Sorry for the delay, but I just now have uploaded the simple
> arm
> > > model
> > > > that I had written about last week.
> > > >
> > > > Thanks for all your help with this.
> > > >
> > > > Sarah
> > >
> > >
> > >
> > >
> > > AnyBody Technology provides free support on the use of the
> AnyBody
> > > Modeling System and the Scripting language AnyScript. Other users
> are
> > > welcome to join the discussions.
> > >
> > >
> > > YAHOO! GROUPS LINKS
> > > Visit your group “anyscript” on the web.
> > > To unsubscribe from this group, send an email to:
> > > anyscript-unsubscribe@yahoogroups.com
> > > Your use of Yahoo! Groups is subject to the Yahoo! Terms of
> Service.
> > >
> >
> >
> > –
> > Sarah R. Sullivan
> > PhD Candidate, Biomedical Engineering
> > Rutgers, The State University of New Jersey
> > Piscataway, NJ 08854
> > sarsulli@e…
> > 908-420-3371
>
>
>
>
>
> AnyBody Technology provides free support on the use of the AnyBody
> Modeling System and the Scripting language AnyScript. Other users are
> welcome to join the discussions.
>
>
>
> SPONSORED LINKS
> Biomedical engineering degree
> Biomedical engineering career
> Biomedical engineering program
> Biomedical engineering
> schools Biomedical
> engineering jobs Biomedical
> engineering
> YAHOO! GROUPS LINKS
> Visit your group “anyscript” on the web.
> To unsubscribe from this group, send an email to:
> anyscript-unsubscribe@yahoogroups.com
> Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
>
–
Sarah R. Sullivan
PhD Candidate, Biomedical Engineering
Rutgers, The State University of New Jersey
Piscataway, NJ 08854
sarsulli@eden.rutgers.edu
908-420-3371
Hi Sarah,
- Balancing the model
Now I understand your problem much better. It is important to
understand that we distinguish sharply between kinematics and
kinetics in AnyBody. Setting a driver to 0 or any other static value
is kinematics and has no bearing on the equilibrium of the model. The
driver does not change its kinetic characteristics because you set it
to a specific value. This is the reason why the model is not getting
balanced just because you set the value of the shoulder driver to
zero.
But each driver has a property called Reaction.Type. When this is set
to 1 for a particular degree of freedom, then it means that this
degree of freedom is being carried by the driver and hence does not
have any need for muscles. This is pure kinetics, so whatever
movement the driver is imposing on the degree of freedom has no
bearing on the driver’s ability to carry the load. Please notice
that
if the DOF is moving and has Reaction.Type = 1, then the driver is a
motor and will add to the energy balance of the system.
- Reaction forces
The uploaded model has the following values for shoulder reaction
forces:
x: -174 N
y: -436 N
z: 0 N
- Interpolation of sampled data
When you import sampled data into an interpolation driver, the system
automatically generates a mathematical interpolation function through
the data. This means that your subsequent access to the data is
really evaluations of the interpolation function. This is independent
of the sampled data, so the sampling frequency makes no difference.
However, please notice that sampled data of high frequency may be
infested with noise. The system often differentiates the data during
the analysis, and this amplifies the noise by an order of magnitude
for each differentiation. Hence you can end up with very inaccurate
input. It is usually advisable to filter the data outside AnyBody and
possibly to downsample it before you use it. It is very important to
check the resulting interpolation function and its derivatives after
you have loaded it into the system. You can do this in the chart
view. Watch out for oscillations or large numerical values of the
derived functions.
Best regards,
AnyBody Support
— In anyscript@yahoogroups.com, “Sarah R. Sullivan” <sarsulli@e…>
wrote:
> Thanks for the quick reply. A couple of quick questions.
Regarding the
> arm model with two revolute joints - I will still need two muscles
to run
> the situation even if I have set the joint to be in one position,
with no
> velocity? Isn’t that fixing the degrees of freedom? Or not
totally?
>
> And also, can you give me a quick result of the shoulder forces you
are
> getting? I did the math myself to get something along the lines of
> Fx=-440 and Fy = -~730 (off the top of my head). When I did it out
by
> hand, the shoulder reaction forces never changed when I varied the
number
> of muscles (or those involved) in the model. I’m not sure why I was
> getting zero for both Fx and Fy, but I wasn’t getting any values.
I’ll
> have to take a look at it again.
>
> And also, on another note, can AnyBody handle a model being driven
by
> different sampling rates? For example, if I drive the kinematics
with
> 60Hz data, and the kinetics with 240Hz data, will I have to
upsample or
> downsample to get the model to run? Will I need to set the time
step to
> one of those two values, and then change the other data?
>
> Thanks again for your time,
> Sarah
>
>
> > Hi Sarah,
> >
> > In that case the explanation is quite straight forward: The arm
model
> > has two revolute joints and hence two degrees of freedom. This
means
> > that there is no way to balance it with only one muscle. You
need at
> > least two independent muscles when you have two degrees of
freedom.
> >
> > Brachialis and Biceps Short both span the elbow joint, so if you
only
> > have those two muscles in the model, then you have nothing to
balance
> > the shoulder joint.
> >
> > The problem with the lacking shoulder reaction still remains to
be
> > solved. When we run the model you have uploaded, we do indeed get
> > shoulder reaction forces. Should this problem be present in the
> > uploaded model, and if not could you upload a model that
exhibits the
> > problem?
> >
> > Thanks,
> > AnyBody Support
> >
> >
> > — In anyscript@yahoogroups.com, “Sarah R. Sullivan”
> > wrote:
> > > Hi,
> > >
> > > The model failed the inverse dynamics analysis when I only
included
> > 1
> > > muscle in the analysis. For example, if I only included the
> > brachialis
> > > and nothing else, the muscle recruitment analysis failed. I
was
> > using the
> > > demo version of AnyBody 2.0. I also had this same problem
with a
> > couple
> > > of two-muscle contribution combinations (such as an analysis
with
> > the
> > > biceps short and brachialis). And lastly, when running a
successful
> > > model, with multiple muscle scenarios, I was not getting any
> > shoulder
> > > reaction.
> > >
> > > I hope this helps with troubleshooting! Let me know if this
doesn’t
> > > answer any questions and I will try to troubleshoot a little
here
> > as well.
> > >
> > > Thanks,
> > > Sarah
> > >
> > > > Hi Sarah
> > > >
> > > > I have just tried your SimpelArm model, but i have problems
> > making
> > > > it fail the muscle recruitment as you describe. I have
tried two
> > > > version of AnyBody 1.3.1 and 2.0, both of them without
problems.
> > I
> > > > have also tried to add in the outcommented muscles and some
> > motion
> > > > to the elbow it all worked. Please let us know which
version of
> > > > AnyBody you are using?, this can be seen by clicking
> > “Help” in
> > > > the
> > > > menu and then “About”. This will help us
solve the
> > problem.
> > > >
> > > > Best regards
> > > > AnyBody Support
> > > >
> > > >
> > > > — In anyscript@yahoogroups.com, “Sarah R.
> > Sullivan”
> > > >
> > > > wrote:
> > > > > Hi,
> > > > >
> > > > > Sorry for the delay, but I just now have uploaded the
simple
> > arm
> > > > model
> > > > > that I had written about last week.
> > > > >
> > > > > Thanks for all your help with this.
> > > > >
> > > > > Sarah
> > > >
> > > >
> > > >
> > > >
> > > > AnyBody Technology provides free support on the use of the
> > AnyBody
> > > > Modeling System and the Scripting language AnyScript. Other
users
> > are
> > > > welcome to join the discussions.
> > > >
> > > >
> > > > YAHOO! GROUPS LINKS
> > > > Visit your group “anyscript” on the web.
> > > > To unsubscribe from this group, send an email to:
> > > > anyscript-unsubscribe@yahoogroups.com
> > > > Your use of Yahoo! Groups is subject to the Yahoo!
Terms of
> > Service.
> > > >
> > >
> > >
> > > –
> > > Sarah R. Sullivan
> > > PhD Candidate, Biomedical Engineering
> > > Rutgers, The State University of New Jersey
> > > Piscataway, NJ 08854
> > > sarsulli@e…
> > > 908-420-3371
> >
> >
> >
> >
> >
> > AnyBody Technology provides free support on the use of the
AnyBody
> > Modeling System and the Scripting language AnyScript. Other users
are
> > welcome to join the discussions.
> >
> >
> >
> > SPONSORED LINKS
> > Biomedical engineering degree
> > Biomedical engineering career
> > Biomedical engineering program
> > Biomedical engineering
> > schools Biomedical
> > engineering jobs Biomedical
> > engineering
> > YAHOO! GROUPS LINKS
> > Visit your group “anyscript” on the web.
> > To unsubscribe from this group, send an email to:
> > anyscript-unsubscribe@yahoogroups.com
> > Your use of Yahoo! Groups is subject to the Yahoo! Terms of
Service.
> >
>
>
> –
> Sarah R. Sullivan
> PhD Candidate, Biomedical Engineering
> Rutgers, The State University of New Jersey
> Piscataway, NJ 08854
> sarsulli@e…
> 908-420-3371