> A real good ABS must be progressive, take MANY samples per rotation,
> gradualy reduce the breaking power as needed acording to the breaking
> related torque and wheel load. In short, find the limit of adherance and
> stay around it untill you stop.

That won't work, as once you get past the limit of adherence, gradually 
reducing the braking power will not stop the wheel locking.  The 
friction gets less, so you need less brake power to lock the wheel, it 
gets slower so friction gets even less etc. it's in a positive feedback 
loop condition.

Once you are past the limit, the best thing to do is to instantly reduce 
the brake pressure completely, this will move the wheel back into the 
region of higher friction as quickly as possible and you can then 
reapply the brake pressure.  It may not seem intuitive though that 
totally releasing the brake pressure will make you stop quicker in the 
end, but consider that 99.9% of the time is probably spent below the 
limit and only 0.1% above the limit with the brake pressure cut.

Of course the faster your system is the less noticeable the "pulsing" is 
and the more you can stay around the limit, but a progressive or gradual 
system is not the best way to do it, and would be much more expensive.

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