Bicycle Fitting with 3D-Model and FullBodyModel

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1

Hello AnyBody Users,
my Name is Jan Eisenhardt. I´m studying mechanical enginering at the
Pforzheim University of applied science (Southwest Germany) Our
Univesity does lots of things around bicycles . (Muliforce testing of
Bicycle frames, Testingbenches for bicycle components…) The last
idea of my mechanical enginnering Professor was, that there should be
a greater optimization-opportunity to fit a bicycle perfect to a
customer than to reduce the weight of the bicycle for another few
grams. Therefor our University bought the AnyBody-License and now it
is my task to write a first thesis about AnyBody an Bicycle fitting.

I trid to find a otimized posture with the Bicycle-3D- and
Fullbody-Model. I did an Parameterstudy with the 3D-Model like it
was shown for the 2D-Model in the Tutorials. What I got is that the
Position for the lowest Metabolism is the lowest and most backward
saddle position. The Position for the lowest MaxAct is the highest and
mostforward position saddle position.

Question one: Is this correct? the 2D-Model shows the position for
the lowest MaxAct, in the highest most backward Position?

Question two:
Is there a way to get a Variable for Metab (.pmet) without searchin
through all muscle files and copying all *.pmet Values for all the
muscles in the whole body? (I also want to find the best Position for
the Upperbody-Position (Position for the Handlebar in the FullBodyModel!)

Question three:
Does anybody has an idea for another Designmeasure or a Algorithm or a
Method to find a rasonable Position for SaddleHight and SaddlePos (So
that I could for example run an Optimization-Study, but without
defining a minimum Seatdistance?)

Thank You!

Jan

2

Hey Jan,

Welcome to the group! And good luck with your thesis.

1: The results are most properly correct, but for the given input. So for
example a different scaled person may of course result in different optimal
positions. Please be also very careful if the applied boundary conditions
really fit to your problem.

2: Unfortunately I’m not aware of a way to use all the Pmet values. But
mostly you will be only interested in specific muscle groups, and therefore
it’s only little effort to define a variable. If you would really use all
the muscles you can us a shortcut to get all the names. Open a ChartFX
window and give Y: Main.Study.Output.Model.....*.Pmet (or the
corresponding expression for your model), then all Pmet values will be plot.
You can export all the data to some other program (excel, scilab, matlab)
and extract the names of the different paths and built your definition for
the variable out of this. This could save some time and makes sure you catch
all of them. This is most probably not a very elegant way, but it should
work.

  1. Of course it depends on the problem you want to address. But for a
    general evaluation of the quality of a seat position Metabolism as well as
    Max. Muscle Activity may be the best candidates.

Best regards,

Sebastian

From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com] On Behalf
Of jan_eisenhardt
Sent: 10. august 2008 13:19
To: anyscript@yahoogroups.com
Subject: [AnyScript] Bicycle Fitting with 3D-Model and FullBodyModel

Hello AnyBody Users,
my Name is Jan Eisenhardt. I´m studying mechanical enginering at the
Pforzheim University of applied science (Southwest Germany) Our
Univesity does lots of things around bicycles . (Muliforce testing of
Bicycle frames, Testingbenches for bicycle components…) The last
idea of my mechanical enginnering Professor was, that there should be
a greater optimization-opportunity to fit a bicycle perfect to a
customer than to reduce the weight of the bicycle for another few
grams. Therefor our University bought the AnyBody-License and now it
is my task to write a first thesis about AnyBody an Bicycle fitting.

I trid to find a otimized posture with the Bicycle-3D- and
Fullbody-Model. I did an Parameterstudy with the 3D-Model like it
was shown for the 2D-Model in the Tutorials. What I got is that the
Position for the lowest Metabolism is the lowest and most backward
saddle position. The Position for the lowest MaxAct is the highest and
mostforward position saddle position.

Question one: Is this correct? the 2D-Model shows the position for
the lowest MaxAct, in the highest most backward Position?

Question two:
Is there a way to get a Variable for Metab (.pmet) without searchin
through all muscle files and copying all *.pmet Values for all the
muscles in the whole body? (I also want to find the best Position for
the Upperbody-Position (Position for the Handlebar in the FullBodyModel!)

Question three:
Does anybody has an idea for another Designmeasure or a Algorithm or a
Method to find a rasonable Position for SaddleHight and SaddlePos (So
that I could for example run an Optimization-Study, but without
defining a minimum Seatdistance?)

Thank You!

Jan

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