This reminds me of a problem one of the prototype Range Rovers (one of
the first vehicles to have ABS) had.
Here's the scenario:
You're off road, climbing a steep hill. You lose traction and the wheels
start to spin like mad. At this point, the ABS controller thinks you're
travelling quite fast.
You slam your foot on the brakes, and the wheels stop spinning. The ABS
controller thinks 'Hey up, the wheels have locked', and releases the
brakes again. You go careering backwards down the hill.

This actually put the release of the model back several months, as they
could not fix the bug in the existing unit, and had to design a new one
from scratch (this was in the days when ABS units were extremely high
tech and phenomenally expensive).

Oyvind Kaurstad wrote:
>
> This is way off topic, but it is related to electronics, and
> could theoretically be related to PIC's... :-)
>
> Modern cars have ABS brakes, which is a system made to
> prevent the wheels from locking up.
>
> This system have sensors on the wheels that senses whether
> it is rotating or not. Usually it is sensing on a toothed disk of
> some kind. (Probably some kind of hall-effect gadget)
>
> This is perfectly suited to sense if there is rotation or not.
>
> But here comes the interesting part:
>
> How can a car with ABS brakes come to a stop in a hill?
>
> Why don't the ABS-system release the brakes when the car stops?
>
> And now you might say that the ABS-system is deactivated below
> a certain speed, which is absolutely correct.
>
> But what if a car standing still starts to slide? Will the ABS-system
> be able to release the brakes?
>
> Just wondering....
>
> -Oyvind

--
------------------- Linux- the choice of a GNU generation.
--------------------
: Alex Holden- Caver, Programmer, Land Rover nut, and Radio amateur (M1
CJD). :
-------------- http://www.geocities.com/CapeCanaveral/Lab/1532/
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