By Nnamdi Ikeh-Akabogu (FRSCN)
An anti-lock braking system or anti-skid braking system (ABS) is an automobile safety system that allows the wheels on a motor vehicle to maintain tractive contact with the road surface according to driver inputs while braking, preventing the wheels from locking up (ceasing rotation) and avoiding uncontrolled skidding.
It is an automated system that uses the principles of threshold braking and cadence braking which were practiced by skillful drivers with previous-generation braking systems.
It does this at a much faster rate and with better control than many drivers could manage.
ABS generally offers improved vehicle control and decreases stopping distances on dry and slippery surfaces; however, on loose gravel or snow-covered surfaces, ABS can significantly increase braking distance, although still improving vehicle steering control.
HISTORY
The first patented system was created by German engineer Karl Wessel in 1928. Wessel, however, never developed a working product and neither did Robert Bosch who produced a similar patent eight years later.
OPERATION
Typically, ABS includes a central electronic control unit (ECU), four-wheel speed sensors, and at least two hydraulic valves within the brake hydraulics.
The ECU constantly monitors the rotational speed of each wheel; if it detects the wheel rotating significantly slower than the speed of the vehicle, a condition indicative of impending wheel lock, it actuates the valves to reduce hydraulic pressure to the brake at the affected wheel, thus reducing the braking force on that wheel; the wheel then turns faster.
Conversely, if the ECU detects a wheel turning significantly faster than the others, brake hydraulic pressure to the wheel is increased so the braking force is reapplied, slowing down the wheel.
This process is repeated continuously and can be detected by the driver via brake pedal pulsation.
Some anti-lock systems can apply or release braking pressure 15 times per second. Because of this, the wheels of cars equipped with ABS are practically impossible to lock even during panic braking in extreme conditions.
The traffic expert is DCC Nnamdi Ikeh-Akabogu, DCC Morning and Evaluation (M&E), Special Duties and External Relations (SEDER), FRCC HQ, Abuja.
