Hi,
I’d like to know if it’s possible to model a trampoline with AnyBody.
In fact, the project will be to try to model a human body which jump
on a trampoline or malleable ground.
Do you think it will be possible ?
Regards,
Arnaud BARRÉ
Laboratoire de recherche en imagerie et orthopédie (LIO)
Centre de recherche du CHUM
Pavillon J.A. de Sève
Hôpital Notre-Dame
1560, rue Sherbrooke Est, local Y-1615
Montréal (Québec) H2L 4M1
Hello Arnaud and welcome to the group!
A trapoline jump sounds like a fun thing to do. The short answer to
your question is that it is possible to some extent depending on the
quality of the input data you have.
Here’s a slightly more detailed answer:
AnyBody is based on inverse dynamics, so it requires the model to
have external boundary conditions for six degrees of freedom. This
means that to model the fly phase you need to do some special
tricks. For reasons of simplicity I will not describe those right
now, but I would be happy to discuss them further on.
The stance phase (when the body is in contact with the trampoline)
is very similar to the stance phase in gait. There are theoretically
two ways to model this:
Using a complete set of movement data for the entire body and no
information about the ground reaction forces from the trampoline.
Using movement data only for the lower part of the body
(depending on where you wish to compute the muscle forces) together
with measured trampoline reaction forces.
Method #2 is by far the more accurate of the two possibilities. If
you are able to measure the trampoline reaction forces, then you can
proceed exacly as for a gait analysis, i.e.:
a. Impose movement data on as much of the body as you want to
include in the analysis.
b. Impose an AnyReacForce (an onbect from AnyScript providing
balance) on the point where you cut the remaining part of the upper
body off. This probably requires some additional explanation, for
but now you just have to trust me that it can be done.
c. Impose the measured trampoline reaction forces on the feet.
You might want to have a look at the Gait2 example in the files
section of the group.
Best regards,
John
— In anyscript@yahoogroups.com, Arnaud BARRÉ <arnaud.barre.1@e…>
wrote:
>
>
> Hi,
>
> I’d like to know if it’s possible to model a trampoline with
AnyBody.
>
> In fact, the project will be to try to model a human body which
jump
> on a trampoline or malleable ground.
>
> Do you think it will be possible ?
>
> Regards,
>
> Arnaud BARRÉ
> Laboratoire de recherche en imagerie et orthopédie (LIO)
> Centre de recherche du CHUM
> Pavillon J.A. de Sève
> Hôpital Notre-Dame
> 1560, rue Sherbrooke Est, local Y-1615
> Montréal (Québec) H2L 4M1