In a message dated 2/26/2006 9:30:13 A.M. Eastern Standard Time,
jacarriere@jacircuits.com writes:
It is also important to know that there are both steady state limits
and dynamic peak metrics that are used to characterize max lateral
acceleration and they are very different. A high performance vehicle
that can pull 1 g on a steady-state skid pad test can typically
generate peak values 20% greater than the steady-state.
We've measured some of the full-zoot SS type cars with a competition
set-up on R compound tires (basically the fastest of the stock class
cars) and see steady state values of ~1.1g. This means dynamic peaks
that are about 25% higher. For purposes of course speed
calculations, I would use the steady state numbers because that is
what the vehicle an sustain.
Here is some g-g data for a SS Elise. Hoosiers / Coarse Asphalt. I ran the
data with no smoothing, just straight 100 hz readings. And again with 1/2
second averaging.
_http://www.pbase.com/sjmarcy/image/56583258.jpg_
(http://www.pbase.com/sjmarcy/image/56583258.jpg) (unsmoothed)
_http://www.pbase.com/sjmarcy/image/56583260.jpg_
(http://www.pbase.com/sjmarcy/image/56583260.jpg) (smoothed)
What would you think might be the best way to smooth or filter? The
smoothing used averages the prior and subsequent 1/4 second. I can also set a
maximum rate of change. Filtration via Butterworth, Chebyshev, or custom with
various parameters. All of this separately or in combination. Simple
averaging
seems to work well, but I wonder if that is best. Thanks.
Stan
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