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RE: Tire reliabilty, traction ,weight sensors

To: "'Rick Hammond'" <r.hammond@sympatico.ca>
Subject: RE: Tire reliabilty, traction ,weight sensors
From: "Albaugh, Neil" <albaugh_neil@ti.com>
Date: Mon, 3 Dec 2001 10:55:17 -0600
Rick;

Measuring lift/downforce at each wheel is certainly feasable. Rough surfaces
will show up as variations in the reading unless you low- pass filter the
outputs. If the outputs of your sensor are low- pass filtered, you are, in
effect, doing a running average of the outputs. This smooths out the bumps
and gives you the average of the reading, which is the reading of net lift
or downforce.

Reading the vertical position of each wheel and calibrating your spring rate
(wheel rate, actually) then gives you the output in volts per inch of
deflection. Shocks won't mess up the reading unless they have lots of
"stiction" but even this is doubtful when the wheel is being vibrated up &
down. Calibration of the wheel spring rate is probably best done with the
shock removed, though.

Regards, Neil   Tucson, AZ

-----Original Message-----
From: Rick Hammond [mailto:r.hammond@sympatico.ca]
Sent: Saturday, December 01, 2001 12:07 PM
Cc: land-speed@autox.team.net
Subject: Re: Tire reliabilty, traction ,weight sensors


Hi All,
Not to dive into the TC thing but I have ridden some scary pickups down icy
hills
off-road and I'm not a fan of those anti-lock brakes.  I know you weren't
refering to
bikes, but at speed what about the throttle as part of the steering?  I
wouldn't
want a
system in the middle of that.  My microprocessor has an ear on each side.

On the other hand, there's nothing wrong with data aquisition.  I think it
would
make
sense to have maybe a bar gauge showing the amount of wheel-slip.  The
driver
could
then decide on his comfort level.
(ok, I guess I did dive in)

The other data aquisition item I was wondering about though would be for the
downforce/lift at speed.
I'll be set up with 4 coil springs; has anyone mounted any weight sensors
(pressure
sensors?) to record the weight supported by each spring?  Would these be
upset
by rough
surface?  Ideally they shouldn't but would the shocks mess things up?
I'm not talking second to second, but to know if the rear end gets light at
100...140...etc.
Hmmmm?
Cheers,
Rick

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