Research On Electric Braking System For Electric Vehicle

With the increasingly complicated of road environment, people will be more and more high to the requirement of automobile braking performance.When the brake initial speed is constant, The main factors that affect the braking performance of the vehicle are the response time of the brake and the utilization rate of the wheel to the ground. Compared with the current vehicles use hydraulic or pneumatic braking can be seen to electro-mechanical brake (EMB) adopted the full line of control,which has braking response time is fast, eliminate brake clearance quickly, high utilization of space and a simple structure etc. So that it can effectively shorten the braking distance. When using a more effective anti-lock braking (ABS) control, make the vehicle to maximize the use of road adhesion, the braking distance will be further reduced. If take the EMB and ABS can be combined to the vehicle brake technology brings the face take on an altogether new aspect. Therefore, it is an urgent task to study the relevant theory of ABS on the basis of EMB system, which can significantly improve the car’s driving safety and so on.In this paper, a new type of electronic mechanical brake actuator is designed, the vehicle antilock brake control to a certain degree of research, the main research contents are as follows:(1) This paper introduces a new type of braking device-electronic mechanical brake (EMB), composition of EMB system are analyzed in detail and the typical structure of EMB actuators, on the basis of this paper expounds the function and meaning of ABS+EMB.(2) Selection criteria and selection process of EMB system are given draw up, on the basis of the EMB transmission device is self-designed. The device comprises four power sources motor, a speed reduction and torque increasing device, a ball screw mechanism and a force self-amplifying device.In accordance with the selection process of the above agencies have been related to the size of the calculation, and the completion of the sub system of the check.(3) In order to quickly eliminate the EMB system in braking condition of brake clearance, speed-current double closed loop PID controller is designed. In MATLAB/ Simulink interface built in brushless DC motor model of each part and controller model. On this basis to eliminate brake clearance condition to carry on the simulation experiment analysis, the results show that the controller can meet the requirements of this system.(4) Comparative and analysis to the vehicle’s anti-lock brake system of the advantages and disadvantages of several common control strategy. According to the characteristics of ABS, the two control algorithms of sliding mode and fuzzy sliding mode based on EMB system are derived.(5) Under MATLAB/Simulink interface has set up a general simulation model for the EMB+ABS, includes a quarter vehicle model, tire model, EMB actuator model, the sliding mode controller and a fuzzy sliding mode controller model. Using sliding mode algorithm and fuzzy sliding mode algorithm in a single straight road and jump road simulation experiment are carried out of the ABS system, the simulation results of these two control algorithms are compared. The results show that the braking performance and robustness of the latter are better than that of the former, and the system can well adapt to the changes of pavement condition.(6) In order to further improve the control effect of EMB system, composite PID control strategy is used for EMB actuators at different stages of optimization control. In single and jump pavement compared with fuzzy sliding mode control for the simulation and analysis, the results show that the composite PID control strategy can better to effectively control of EMB+ABS.