Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!sequent!muncher.sequent.com!gil
From: gil@sequent.com
Newsgroups: sci.electronics
Subject: Re: measuring vehicle speed
Keywords: car speed
Message-ID: <1991Jun18.214122.29348@sequent.com>
Date: 18 Jun 91 21:41:22 GMT
References: <31487@hydra.gatech.EDU>
Sender: news@sequent.com (News on Muncher)
Organization: Sequent Computer Systems, Inc.
Lines: 22

In article <31487@hydra.gatech.EDU> gt0297a@prism.gatech.EDU (Tim Drury) writes:
>is there an accurate, *cheap* method of measuring vehicle speed without
>measuring off the front or rear wheels?  this is to be used in a proto-
>type traction control system on a race car.  the speed of the rear
>wheels will be compared with the true vehicle speed to determine if
>traction is lost.  since the front wheels will rotate at differing speeds
>in turns they can't be used.
>is there an easy way to use infrared doppler or something like it?

It would seem to me that the inaccuracy caused by the front wheels turning on
different radii would not be any worse than the inaccuracy of a doppler on a
cornering device, since the doppler would only measure the velocity in one
plane, while the vehicle would be moving in two planes.  Why not do the same
trick that car tests do, and use an electronic speedo on a bike wheel attached
to the rear bumper?

Gil
-- 
Gil Meacham                  ____  ____ _ __ __
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