Hello Chris,

The rows are each corresponding to one degree of freedom. In principle, you

do not know any more about the rows. It is not like you might imagine that

each row was liked to a certain kinematic property in the model (e.g. a

kinematic measure), at least it does not have to be like this. A row can, in

general, be associated with any combination of kinematics.

However, in the current format, I think that each row is actually associated

with one degree of freedom of a segment; so the first six rows are first 3

translational then 3 rotational degrees of freedom of the first segment and

so on.

I cannot recall whether the file also contains a list of segments name, but

if so, this list is ordered like these blocks of 6 rows.

I state it this way because there is no guarantee that it will stay like

this for all model setups. The data are outputted directly for the

computational kernel of AnyBody, so it will reflect whatever algorithm that

is forming the equations of motion.

The columns of Cm each correspond to one muscle and they are ordered like

the list of “Strong Muscles” in the file.

Similarly, each column of Cr corresponds to a component of a reaction force

with Type equal to On. As far as I recall, the names of the reaction force

are not outputted to the file.

Could you explain what kind of information you would like and the task you

need it for?

We are always open for improvements.

If you for instance are using the equations to do your own muscle

recruitment analysis in external software or your own code, we would be very

glad to know what criteria you are looking for (but obviously didn’t find)

in AnyBody.

Best regards,

Michael

Michael Damsgaard, AnyBody Support

www.anybodytech.com

From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com] On Behalf

Of chrisjgatti

Sent: Friday, August 01, 2008 13:11

To: anyscript@yahoogroups.com

Subject: [AnyScript] Re: Equations of motion

I have figured out how Cm, Cr, and R are used, but I am unsure about

what the rows and columns correspond to. Is there a way to list out

each row or column name such as which muscle or DOF they correspond to?

Thanks.

Chris

— In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com,

“chrisjgatti” <cjgatti@…> wrote:

>

> Check that … R is 1 x 114. Excel combined some cells initially.

>

> — In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com,

“chrisjgatti” <cjgatti@> wrote:

> >

> > I see in the reference manual that the equations of motion can be

> > exported using EquilEqExportFileName inside AnyBodyStudy. I have

> > exported these as a text file and could use some help deciphering what

> > is output.

> >

> > First, all of the segments are listed and I understand that. Then,

> > muscles are listed twice; the first time they are just named ‘Muscles’

> > and the second, they are named ‘Strong Muscles’, but both groups have

> > the same muscles listed (172 in the model including extraneous muscles

> > like th GHReaction muscles…which is more than the 114 in the arm

> > model I am using). What is the difference between ‘Muscles’ and

> > ‘Strong Muscles’?

> >

> > Then there is actual data, with variable names t, Cm, Cr, and R. What

> > are the last three? Cm is 114 x 172 (rows x columns), so I assume has

> > something to do with the 114 real muscles and the 172 muscles listed

> > at the top of the file. Cr is 114 x 79 and I don’t know what the 79

> > corresponds to. R is 1 x 100 and I don’t know what this is either.

> >

> > What is the general form of the equations with respect to the output

> > variables? Any other hints or tips about these equations of motion

> > would be appreciated as well. Thanks.

> >

> > Chris

> >

>

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