| Hydraulic Control Unit (HCU) is key part of Electric Hydraulic Brake .As a typically active control technology of automobile, EHB can accurately control the number of brake liquid entering into brake cylinder, through monitoring the state of vehicle & road by sensors. And then control the rotating movement of the wheels and improve vehicle driving ability and braking stability. EHB system usually contains electric pedal unit, hydraulic pressure generate and control unit, and series of sensors. The electric pedal unit reflect driver's intention and transmit the signal to the Electric Control Unit (ECU).The hydraulic control unit accommodate the pressure in the wheel cylinder according to different working states.This paper mainly do some basal and exploring work, the following research has been completed.1. The development of HCU goes with the development of EHB. The abroad research on EHB started from the early 1990s. Since the first practical EHB was equipped on vehicle in 1996, Numbers of automobiles agents and R&D associations have been interested by the excellent quality, and started on researching it. EHB is an important step to the brake-by-wire. Nowadays, EHB has been applied in some luxury automobiles. For it is high cost and technology monopolization, there is a long way to make EHB popular. Researches on HCU are in commencement phase in China.2. This paper introduces the basic principles and implement project of EHB in brief, and analyses their constructions, layout, performance, etc. The composed parts of HCU are also introduced and how to perform the order of system for pressure control. Designed method of hydraulic system is according to vehicle parameters. The valves act as primary components of the brake pressure modulator, and its response characteristics influence the response of hydraulic system directly.3. The design of valves is main part of this paper. To choose the component of hydraulic control unit is our first thing. The part parameter determination is carries on in the foundation which the overall system pressure and the current capacity determined. The definite parameter is the base of part chosen. So long as elects the part approaches the parameter request, can achieve the functional need, the chosen is ok. After determined the pipeline the caliber, refers to the designate on the part external dimensions, designed the hydraulic control unit valve body pipeline portal frame construction, and enabled it to realize the control function of ABS, ASR and ESP system and so on.4. The research on fuzzy control logic and make it definite that how EHB system implement basic brake on high-μ, middle-μand low-μroad. Then, dynamic simulation models of vehicle system are established with Matlab/Simulink toolbox, and simulate several operating modes. The contrast between the traditional and EHB brake hydraulic pressure is got by experiment which shows the latter one is much better than the former one. The results show that EHB can effectively improve the braking ability of automobile. This paper also finished the research that EHB carry out antilock braking on a middle-μand low-μroad. During the controlling process, it recommend and introduces the usual technology about estimation of vehicle velocity, road identification and antilock braking control logic and so on, which establishes the foundation for developing the brake control strategy that suits for the whole operating mode in the future. The simulation results indicate that not only the hardware of EHB but also the way of control is better than traditional brake system at improving the braking ability of automobile.
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