[python] Re: Cool handlebar for 48deg 20in
- From: Vi Vuong <vi_vuong@xxxxxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Fri, 18 Mar 2011 21:39:45 -0700 (PDT)
Hi Pascal,
Thanks for the tips and lead to some excellent bike research. The linearized
model has been experimentally validated, so it's good to use. It turns out
that
their code JBike6 also has a recumbent example, a Burley Canto short wheel
base,
so it's not so bad start for the python. The experimental set up is also very
interesting
http://audiophile.tam.cornell.edu/~als93/Publications/KooijmanSchwabMeijaard2008.pdf.
I am not sure about mounting the whole setup on a python - "Sensors are
present for measuring the roll rate, yaw rate, steering angle, and rear wheel
rotation. Data are collected via a USB-connected data acquisition unit on the
laptop computer, mounted on the rear rack". I am thinking more like an iPhone
mounted to the
pivot http://iphonetuts.com/wp-content/plugins/wp-o-matic/cache/3db25_qb6hU.png
Maybe
someone who knows Arend Schwab personally, can also convince him to try a
python...
Vi
________________________________
From:Pascal Buenzli <pascal.buenzli@xxxxxxxxx>
To:python@xxxxxxxxxxxxx
Sent:Thu, March 17, 2011 11:57:30 PM
Subject:[python] Re: Cool handlebar for 48deg 20in
Hi Vi,
Just in passing, to run windows executables directly from Linux, you can use
"wine" (see http://www.winehq.org). Alternatively, if you have at hand a
Windows
OS to install, you can do so in a virtual environment running from Linux. I am
using VirtualBox (http://www.virtualbox.org/) on a Mac to have virtual Linux
and
virtual Windows in similar cases as you, it works perfectly (better than wine
for me for Windows executables). (VBox also runs on Linux and Windows, so you
can have access to the missing virtual OS in any case.)
For your dynamics study (but I think it is quite a tricky problem), you might
be
interested in the scientific article by Meijaard et al. (2007) "Linearized
dynamics equations for the balance and steer of a bicycle: a benchmark and
review", Proc. Roy. Soc. A 463:1955-1982. Full text is available there from the
journal, see pdf link on that page: http://dx.doi.org/doi:10.1098/rspa.2007.1857
Other publications by one of the co-authors can be found there:
http://audiophile.tam.cornell.edu/~als93/Publications/papers.htm
It is applied to conventional bicycle designs, but you might be inspired by
their mathematical/computational methods.
Hope this helps,
Regards,
Pascal
On Thu, 17 Mar 2011, Vi Vuong wrote:
> Hi Dirk,
>
> Just for you, I swapped out the rear wheels to vary pivot angles, from 26,
> 16,
>12, to 6in to get 60-52deg. Surprise, they are all ridable. In fact the
>smaller wheels feel more stable than 26in. Seat height may have something to
>do
>with it, and possibly the wheels themselves. Here is video of the test ride.
>http://www.youtube.com/watch?v=5JUg0zIHSuM
>
> Regarding your program, assuming the geometry calculation is OK, the seat
> rise
>peak still suggests a critical point, compared to the slopes on either side.
>I
>will flip the rear frame back to normal and test 48deg downward until it
>scraps
>the ground, to confirm the critical point hypothesis. Searching the archive,
>it
>seems that Ray had written a program (python?) that included forces on the
>geometry, http://rjs.org/Python/FrameGeometry.zip compiled for Windows, so I
>have to figure out a way run it in Linux. I may take a shot at coding my own
>to
>study dynamics, which may take a while...
>
> Vi
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