What are the advantages of ABS braking systems compared to other hydraulic braking systems?
The advantages of ABS brakes (anti-lock braking system), are just as the meaning of
their acronym implies, they eliminate or greatly reduce the possibility of brake
lock up and therefore provide a better chance of steering out of trouble.
Conventional hydraulic brakes work by using a cylinder (actuator), which squeezes
brake calipers together around the wheel's rotor when the brake petal is depressed.
Difficulties arise with these conventional brakes if the road is slick and the
driver executes a panic stop. Under these conditions the wheels may lock up and
the tires run the risk of losing their grip. When tires lose their grip of the
road, there is a good chance that the car may go into an uncontrolled spin. This
is why drivers in older vehicles have been taught in the past to pump brakes when
on icy roads.
ABS brakes were designed to combat the problem of tire lock up and uncontrolled
spins. Since brakes are most effective at slowing the car at a point just before
wheel lock up, a system that provides for wheel braking while preventing wheel lock
up is very desirable.
Anti-lock brakes do just this by using a computer processor to monitor and control
the application of the brakes. At braking, the processor monitors rpm and braking
pressure on each of the vehicle's wheels. With this information, measured amounts
of pressure are sent to each wheel in the form of hydraulic pulses of pressure to
the calipers. These pulses achieve the desired braking pressure without allowing
the wheels to lock up.
Stephen Portz, Technology Teacher, Space Coast Middle School, FL
'The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative... '