Characteristic Analysis And Control Of The Composite Brake System Based On EHB And EMB

The main direction of vehicle brake is the Brake-By-Wire system which has been widely used. Currently, the more mature brake system are Electro-hydraulic brake system(EHB) and Electro-mechanical brake system(EMB), both of them have their advantages and disadvantages, Hybrid-mechanical brake-by-wire system become the latest concept which is being developed. This paper proposed a Composite Brake System(CBS) with electrohydraulic brake(EHB) equipped on the front wheels as well as the electromechanical brake(EMB) equipped on the rear wheels, which will better meet the needs of the brake by wire systems. Firstly, this paper did the analysis of the EHB and EMB respectively, secondly, set up the platform which had been used for characteristics test, then studied the accurate braking force control algorithm for the two brake system respectively, and improved the control effect by the compensation, then, accomplished the building of the CBS platform via FlexRay networks and Simulator, finally, this paper had made the study of the coordinated control algorithm between front and rear axle braking force distribution which had been verified via the test bench.For EHB system, firstly, this paper carried out the analysis and characteristics test of the HCU, including the choice of the fundamental frequency, wire control range of the electromagnetic valve, characteristic test of high-pressure accumulator and solenoid valves. According to the results of characteristics analysis, this paper did the study of the accurate brake force control algorithm of the EHB system with the applying of pressure and current PID control, fuzzy algorithm was then used to obtain the parameters self-tuning PID parameters, at last,this paper proposed the feed-forward compensation control to solve the nonlinear characteristics.Finally, according to the ideal braking force distribution strategy, this paper proposed the coordination control algorithm which based on different characteristics of the actuators between the front axle and the rear axle.