What are the basic physics or theories behind ABS?

Most people have read the basic version doled out through the press. It usually reads something like this: "ABS prevents lock-up of the wheels under braking by modulating the brakes up to 30 times a second, thus preserving steering ability." There are two major problems with this sort of description because of the misconceptions that it creates: • ABS does indeed prevent lock-up of the wheels while braking. However, this implies to many people that ABS monitors only for wheel lock (as in, absolutely zero rotation). This is not the case. • The implication is that, when invoked, ABS simply turns the brakes on and off 30 times every second, simulating Superman pumping the brakes on and off 30 times a second. This could not be further from the truth. ABS never allows wheel lock on purpose, even for a microsecond. ABS is better described as a braking and stability optimizer. Automobile industry lawyers are probably quivering at such a statement. This is a possible reason why ABS is rarely ...  more