Performance of passenger vehicle anti-lock braking system : an experimental study
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This dissertation describes a comprehensive study of passenger vehicle anti-lock braking systems (ABS). A literature review is presented related to studies that have examined the effects of applied brake pedal force, vehicle speed at brake initiation, tire inflation pressure, and steering inputs on vehicle braking performance. It was found that there is a general lack of literature addressing these critical issues related to performance of passenger vehicle anti-lock braking systems. Based on this review, a study was designed. Extensive road testing was conducted with six fully instrumented passenger vehicles. The vehicles, support equipment, and all sensors and instrumentation are described in detail. The methods used to reduce and analyze raw data collected from the experiments are also described, and program listings are provided. Experimental results are presented for straight-path braking and for combined braking and steering tests. Typical data is presented graphically for each of the experiments and for each of the vehicles studied. The longitudinal acceleration collected during each test is used as a primary measure of braking system performance. The effects of applied brake pedal force, vehicle speed at brake initiation, tire inflation pressure, and steering inputs on performance of passenger vehicle anti-lock braking systems is discussed in detail. It was found that applied brake pedal force and tire inflation pressure do not have a significant effect on ABS braking performance. ABS braking performance increases with increasing vehicle speed. The application of ABS braking with steering maneuvers increases the rate at which the vehicle decelerates. Application of ABS braking before steering input provides better average deceleration than application of ABS braking afterwards. No serious anomalies were found with the ABS braking performance of any vehicle studied. ABS braking has the potential to improve braking relative to locked wheel braking by about 20 percent at most, but most systems improve braking by about 10 percent. The result that increasing speed increases the deceleration performance of ABS braking was in direct opposition to how speed affects locked-wheel braking.