Research On The Adaptive Frontlight System Of Vehicle

As the society developing, vehicles, which are taken as the symbol of civilization and development of the era, come into our everyday life with large numbers. Vehicles make our life faster and more convenient. But at the same time, they put great pressure on the traffic and cause traffic accidents frequently which have great influence on our life security and property loss. Therefore, it's urgent and of great meaning to research on vehicle safe driving for decreasing the traffic accident ratio.According to the related statistical data, the traffic accident ratio at night is 3 times than that in daytime, while the traffic accident ratio on the well illuminated road is 30% of that on the bad illuminated road. And the Large-scale traffic accident at night, 60% of which occur on the curve road with bad illumination, is 1.5 times than that in daytime. Among the reasons of high traffic accident ratio at night, bad vision is a very important factor. So accordingly, how to improve the illumination at night, especially on the curve road, becomes the key issue of vehicle research. Then AFS(Adaptive Frontlight System) comes out at this proper moment.The vehicle AFS has a real-time signal acquisition unit which can acquire signals of the angle of the steering wheel and the vehicle speed in a set time interval. And then the turning angle control program of the frontlight in the ECU(electronic control unit) turns these signals into the needed frontlight turning angle and the needed control pulses. These control pulses are transmitted to the Stepper Motor Driver for driving the stepper motors which make the frontlight precisely turning with the steering wheel. The turn of frontlight provide well illumination for the front and curve road which enlarge driver's vision, so improve the security of driving at night.This paper does a all-around research on the AFS: it first designs and manufactures the Adaptive Frontlight mechanism which could be drove by a rocker, this mechanism is simple but convenient and reliable; chooses related steppers motor for driving the frontlight mechanism, schedules a whole control strategy for the stepper motor; and by using WinIo, programming for achieving communication using PC's parallel port which can precisely driving stepper motors and the frontlight mechanism; calculate several vehicle safe braking distance according to the theoretical rules, after fitting these data by MATLAB it gets the relation formula between vehicle speed and vehicle safe brake distance; then taking the vehicle safe braking distance as the judge principle of the frontlight effective illumination, it builds the relation among the turning angle of frontlight, vehicle speed and vehicle front wheel turning angle, and the rationality and precision of the relation is verified by graphic simulation; a real-time signal acquisition system is build which can acquire signals of the angle of the steering wheel and the vehicle speed in a set time interval; at last, it builds the experiment plat, through experiments, it is verified that this AFS system is precise, reliable and stable.