The Fuzzy Control Research Of The Air ABS On Medium-duty Truck

Anti-lock braking system (the shortened form is ABS) is a kind of active safety device which can adjust the braking pressure automatically, prevent wheel from being locked up, and keep wheel on the optimal slip-ratio. It can decrease stopping distance, improve direction stability capability and keep steer-handling capability. At present ABS is the advanced technology which is used widely and can improve the safety capability of automobile most effectively, and has become the key part of modern automobile. Now ABS is very popular in several developed country. But in our country, the start of ABS research is late comparatively, and we lack the knowledge property right of ABS product, so the installation ratio of automobile ABS is not high, ABS is used mostly on top grade car and top grade passenger car, and the markets of ABS in China are occupied by the foreign manufacturers mostly. Hence the research of ABS technology has practical significance to the development of Chinese automobile industry, and corrently has become the important topic of Chinese automobile field.This thesis mainly studied the air ABS technology of medium-duty truck. Using the mechanism-electron control technology on the traditional medium-duty truck, it had realized the anti-lock braking of wheel to improve the safety capability of medium-duty truck. The thesis discussed the basal theory, the common structure, the main types and performance principle of ABS in details. According to the character of medium-duty truck and the air braking system, the thesis studied concretely the structure project and control method of medium-duty truck's air ABS.The air ABS of medium-duty truck studied in this thesis included three parts: braking pressure adjustor, rotate speed sensor of wheel and electronic control unit (ECU). And it used the structure project with two channels and three sensors, and used the fuzzy control method based on the control of slip-ratio. For achieving the dynamic simulation of air ABS, four math models whole vehicle model, single wheel model, tire model and arrester model were built in thesis. In order to expound the principle of fuzzy control from the side of theory, the thesis described the fuzzy sets theory, membership function, fuzzy discursion and fuzzy logic control theory clearly. And using the fuzzy toolbox of Matlab/Simulink software, the adaptive fuzzy controller was designed to match the air ABS. Then using the math models, the whole Air ABS was simulated in the environment of Matlab/Simulink software. The results indicate that air ABS has remarkable effect on the aspect of decreasing the stopping...