Project On Anti-lock Braking System used For Automobile CarsINTRODUCTION
Anti-lock braking systems (ABS) use electronic controls to maintain wheel rotation under hard breaking that would otherwise lock a vehicle’s wheels. Keeping the wheels rotating increases vehicle stability, especially when tire/roadway friction is reduced or varying, as when the pavement is wet. Prior general understanding of the relationship between improved braking and safety, together with earlier specific literature on antilock braking, leads one to anticipate a complex interaction between ABS and safety. Test track evaluations have convincingly demonstrated the technical advantages of ABS under a wide variety of conditions. A study analyzing historical traffic crash data for a non-ABS vehicle fleet predicted that universal ABS in Germany could diminish severe crashes by 10 to 15%. However, when taxi drivers in Munich were randomly assigned vehicles with and without ABS, no overall difference in crash rates between the two groups was observed, although each group experienced different types of crashes. Because the severity of crashes apparently induced by ABS was less than that for the crashes prevented, the study suggests that the ABS system led to a net reduction in harm. An analysis of Swedish insurance data uncovered associations between the rates of occurrence of different types of crashes and ABS. An analysis of Canadian insurance data found a 9% reduction in claim frequency, but a 10% increase in average claim severity. The Highway Loss Data Institute found no change associated with ABS in either the frequency or severity of traffic crashes. A study using police-reported crashes per registered vehicle reports a 6% to 8% reduction in crash risk due to ABS, while another study using fatal crashes finds an increase in risk to occupants of ABS equipped vehicles but a decrease in risk to other road users. The present paper aims at increasing understanding about the relationship between ABS and traffic safety by summarizing the results of two recent studies, augmenting these results with additional data and findings, and then comparing the results to other results in the literature. The first of the two studies examined how ABS affects the relative risk of crashes in general under different roadway, environmental, and other conditions using data on police reported crashes from two states. The second study was confined to two-car crashes, and examined the following two questions: How does ABS affect a vehicle’s risk of crashing into a vehicle it is following? How does ABS affect a vehicle’s risk of being struck in the rear? This study used data from five states. In the present paper the results of the first study are updated by including data from all five states.
|Image Courtesy: IIT,Kanpur ABS Project|
Anti-lock 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 a driver could manage.
ABS generally offers improved vehicle control and decreases stopping distances on dry and slippery surfaces for many drivers; however, on loose surfaces like gravel or snow-covered pavement, ABS can significantly increase braking distance, although still improving vehicle control. Since initial widespread use in production cars, anti-lock braking systems have evolved considerably. Recent versions not only prevent wheel lock under braking, but also electronically control the front-to-rear brake bias. This function, depending on its specific capabilities and implementation, is known as electronic brake force distribution (EBD), traction control system, emergency brake assist, or electronic (ESC).
Advantages of Anti-Lock Brakes
The main benefits of an anti-lock brake system (ABS) include.
• Stopping on ice. As mentioned above, an ABS prevents lock-ups and skidding, even in slippery conditions. Anti-lock brakes have been proven to save lives in some situations by helping drivers keep control of a vehicle.
• Lower insurance costs. Because it is a thoroughly tested safety device with a track record of effectiveness, insurers often give customers specific discounts for having an ABS system on their vehicle.
• Higher resale value. As a feature on a car or truck, an ABS raises the market value of the vehicle. Nowadays, where ABS technology has become standard on many vehicles, not having it could result in a lower price for resale.
• Traction control. An ABS shares some of the infrastructure of a traction control system, where new technology helps ensure that each wheel has traction on the road. That makes it easy for manufacturers to install both of these features at the factory.
Disadvantages of Anti-Lock Brakes
Despite the fact that anti-lock brakes are proven to be a safety feature in most situations, and insurers consider them to significantly lower risk for a vehicle, not all drivers are sold on this option for a car or truck. Here are some of the down sides that drivers find in this kind of brake system.
• Inconsistent stop times. Anti-lock brakes are made to provide for surer braking in slippery conditions. However, some drivers report that they find stopping distances for regular conditions are lengthened by their ABS, either because there may be errors in the system, or because the clunking or noise of the ABS may contribute to the driver not braking at the same rate.
• Expense. An ABS can be expensive to maintain. Expensive sensors on each wheel can cost hundreds of dollars to fix if they get out of calibration or develop other problems. For some, this is a big reason to decline an ABS in a vehicle.
• Delicate systems. It's easy to cause a problem in an ABS by messing around with the brakes. Problems include disorientation of the ABS, where a compensating brake sensor causes the vehicle to shudder, make loud noise or generally brake worse.