| With the rapid development of automobile control technology,the control of autoparts gradually tends to electronization.As a type of Brake-by-wire system,electro-hydraulic brake system (EHB) combined the electronic control technologywith the traditional hydraulic braking system.It’s the bridge of traditional brakingsystem to electro-mechanical braking system(EMB). Because EHB retains thetraditional hydraulic system, the reliability of the system can be ensured. At the sametime, through the electronic control it can realize accurate adjustment on wheelcylinder pressure and increase the efficiency of the brake. Therefore, the in-depthstudy of electronic hydraulic brake system has very important significance. Based onthe school-enterprise cooperation project NEHB, a new form of EHB, This paperstudys NEHB through the theoretical simulation and experimental research. The mainresearch work and achievements include the following several aspects of content:The structure and performance characteristics of EHB are analyzed and studied.It introduces the research situation of EHB at home and abroad, and the structure andworking principle of NEHB is also introduced.This paper analyses and establishes the mathematical model of NEHB system’simportant component,and it establishes the simulation model of the whole system byusing AMESim. At the same time,the control strategy of motor pump and high-speedswitch electromagnetic valve is studied. It adopts PID control on the motor speed andPWM control on the reducing valve. It gets the ideal pressure following result onwheel cylinder by simulation.The NEHB test bench is designed and established. The hydraulic actuator andelectronic control system are designed individually.The design on hydraulic actuatormainly includes the brake pedal and master cylinder unit, motor and plunger pump,high-speed switch electromagnetic valve. The design on electronic control systemmainly includes upper and lower computer, hardware circuit. Then, the whole NEHBsystem test bench is set up.The experimental study is carried out base on the NEHB test bench. It analysesthe factors affecting the pressure building rate and pressure maintaining process bythe test of pressure building and pressure maintaining.It meets the test requirements by enhancing seating to the valve and improving the oil pumping way to the plungerpump.Then,the pressure following test of wheel cylinder is done. The expected wheelcylinder pressure curve is fitted according to the ideal pedal displacementrelationship with the wheel cylinder pressure of simulation results. The actual wheelcylinder pressure can follow the target pressure well by controlling the motor and thevalve appropriately. Experimental results are consistent with simulations resultsbasically.It verifies the correctness of the simulation model,at the same time,the goodresult of wheel cylinder pressure following sets the stage for the test in the future. |
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