Research On The Key Technologies Of Controller Of Automotive Electromechanical Brake System

Electromechanical braking system (EMB) is a new sense of brake system, with the wheel braking force can be accurately distributed, intelligent algorithm is easy to be integrated and braking response rapidly and many other advantages.But the safety problem is always the biggest obstacle to it in the market. In this paper, combined with the project supported by Natural Science Foundation:the research on the key technology of electric vehicle brake by wire system (Project No: LY13E050003), based on the summary of the present research situation of domestic and foreign, according to the special requirements of the brake system, we designed a set of EMB system with high safety and satisfy cost requirements, and researched the related key technology. The main research contents are as follows:(1) Established the function structure of electronic mechanical braking system,and analysed the preliminary hazard. According to the results of the analysis to various hazard model, We defined the corresponding vehicle safety integrity level and design requirements, and found out the weak links in each function module, and put forward the reliability design objectives and corresponding design criteria.(2) According to the inherent characteristics of each core module, we constructed the core function module using the design method of software and hardware redundancy.(3) According to the function characteristics of each module and the topology structure of function frame of the whole system, we designed a on-line fault diagnosis system, made up of local diagnosis module, self diagnosis network unit, as well as the central diagnosis unit. At the same time, we defined a security policy, and established the corresponding strategy base, to deal with the fault when online fault diagnosis system identify it.(4) Studied the braking force distribution strategy of four wheel, analysed the braking force distribution under different operation modes. On this basis, the braking performance are further improved through the integration of the ABS system in electronic mechanical brake system.(5) Through the real car test, we found the designed EMB system meet the national standard GB7258-2012for the requirements of braking distance. Designed the contrast experiment comparing the performance with hydraulic brake system, the results show that the performance is improved compared to the original system.