Study Of Optimum Slip Control In Automobile SBC On Variable Pavement

Since an Automobile having driven on road, it is inevitable that the traffic accident is occurred. The automobile driving safety has been one of much concern questions. The automobile brake performance which it has to do with driving safety directly is important guarantee. The study about the Sensotronic Brake Control (SBC) system of the automobile based on slip and variable pavement has momentous affection for raising driving safety and steering ability and reducing pollution. It is of momentous current significance and research price to make further improvement on the brake performance and to ensure security of people and property.This paper summarizes the researches and practices on the electric control brake system of foreign and internal, analyses the structure characteristics and operating principle of the automobile SBC. Because the working condition of motor vehicle in braking is complex and changeable and the more and more high brake initial velocity, the model of considering multiple-factor is important. The brake dynamics model and the second order hydraulic brake system model are built in considering load change and frontal resistance. And the brake system models are analyzed and summarized.The pavement identification and accuracy is a major index for the practicality about the automobile SBC based slip and variable pavement. Those methods of determining optimum slip are presented for experience model and variable pavement in the related documents. This paper presents the method of searching optimum slip by step for the pavements to grade in real-time. The pavement is separated to many different grades. And the different pavement relation to slip isn't same. The road grade is determined by using current estimating braking force coefficient and variation tendency, and the peak adhesion coefficient of the road grade regards as the optimum slip. Comparing to those methods, this method avoids experience model acquired by real-time measuring and calculating and seeking extreme value by using experience model. And each identification slip has a corresponding existing optimum slip. The requirement for accuracy of estimating pavement adhension condition is lower than before, and it accords with reality condition of automobile brake, and demands a few test data.The control tactics of automobile SBC is a key technology of its control system. Considering the complex and changeful practical condition of automobile SBC working condition, the study was presented that combine the fuzzy control, the fuzzy setting-self PID parameters control, the fuzzy slide mode soft-switch control, the fuzzy slide mode direct adaptive control and the H_∞robust control with the automobile SBC system by controlling about identifying pavement in real-time and its optimum slip. Those make the control to achieve better results, and appropriate further for variable pavement. The automobile SBC can make anti-lock of wheel based on five control tactics on variable pavement and high initial brake speed by simulation. The steering stability was enhanced, and the brake distance and brake tome becomes short, obtains good brake effect. The adaptabilities for variable pavement of the fuzzy setting-self PID parameters control, the fuzzy slide mode soft-switch control, the fuzzy slide mode direct adaptive control and the H_∞robust control are more advantage better than the fuzzy control. According to the indexes such as basic brake performances (brake distance, brake time and adhesion condition) and wave size and to realize easy or not at physical, the automobile SBC performances by using the fuzzy slide mode soft-switch control and the fuzzy slide mode direct adaptive control are better than others.The method is presented to analyze the current braking force coefficient signal estimated by model and sensors on variable pavement with multi-resolution analysis, and make the signal of adhesion ability utilization and optimum slip searched to more close practical signal of the current pavment. It can raise the SBC control accuracy. Then the availability is proved by the analyzing results.This paper has fulfilled the experience study for the automobile SBC. Those hardware and software are designed. By experience, it is shown the feasibility and rationality and practicality for developed automobile SBC.