[ODE] Re: Scientific modelling of a runner

[jnilson_99 at yahoo.com]

"What I want to do is estimate the
muscle force needed for bipedal running. "

again, this is trying to estimate every muscle force
in bipedal running, be that human, amphibian or
whatever....


the answer is you need to implement an extremeley
complex neural network to find the realistic output to
which you so desire....


if i'm not being clear then i suggest you implement
Russel Smith's Fox Controller to "at least" simulate
some modicum of muscle movement.

if so,,,then let us know how it goes...


john

--- Martin Baeker <martin.baeker at tu-bs.de> wrote:

> Hello all,
> 
> thanks for the lots of replies to my question. I was
> not in the least
> aware how many people were working in this field
> (because stupid me
> only thought of science, not of things like people
> animations for
> entertainment, movies etc.)
> 
> So here is a more precise description of what I want
> to do, which is
> much simpler, I think, than what my initial question
> implied:
> 
> The problem I am working on is a scientific study of
> bipedal
> locomotion of birds and dinosaurs.  What I want to
> do is estimate the
> muscle force needed for bipedal running. This of
> course depends on the
> exact sequence of motion i.e., on the position of
> the leg segments in
> each part of the gait which is obviously unknown for
> extinct animals.
> 
> Therefore I want to use an optimization procedure to
> find the gait
> with the highest possible speed with a given muscle
> mass. What the
> program I am looking for should do for me is the
> following: Given a
> fixed number (about 5 or 7) of leg positions (that
> was what I meant by
> "frames") , described by the angles between the leg
> segments (angle
> between hip and femur, femur and shank, shank and
> foot, foot and toe)
> at fixed times, calculate the forces and moments
> needed to move from
> one time step to another, including inertial forces
> and ground
> reaction force.
> 
> So the input would look like the following sketches:
> 
> \
>  \
>   \_
> 
>   \
>   /
>   \_
> 
>    /
>   /
>   \_
> 
>     /
>    /
>   /_
> 
> And the output should be the forces and moments
> (averaged over time
> step) on each leg segment needed to get from one
> frame to the next.
> 
> The path of motion from one position to the other is
> rather simple, as
> all angles can be assumed to change by a constant
> rate between the
> steps. So the usual optimization needed in robotics
> is of secondary
> importance here - I simply need a tool to calculate
> the forces and
> moments. In addition, the model is 2-dimensional.
> 
> I hope this describes it more clearly. Can this kind
> of thing be done
> in ODE and, if so, what is the precision I can
> expect on the moments?
> (It was stated that it may be low which would not be
> acceptable here.)
> If not, is there another software available for this
> kind of things?
> It can be done using rigid body dynamics in the
> finite element code
> ABAQUS, I think, but this seems a bit like an
> overkill tool for this problem. 
> 
> Thanks a lot for any help,
> 
> best regards,
> 
> Martin.
> 
> 
> 
>                    Priv.-Doz. Dr. Martin Bäker
>                    Institut für Werkstoffe
>                    Langer Kamp 8
>                    38106 Braunschweig
>                    Germany
>                    Tel.: 00-49-531-391-3073         
>             
>                    Fax   00-49-531-391-3058
>                    e-mail <martin.baeker at tu-bs.de> 
> 
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