| Research of electric vehicle has been promoted by environmental pollution and energy crisis.Compared with the traditional automobile braking system, electric vehicle could extend the mileage by regenerative braking system, and the electro-hydraulic brake system based on EHB has characteristics of high efficiency of braking energy recovery, braking force controlled in real time, good braking efficiency, good braking feeling consistency, etc. Coordinated control of two kinds of braking force in Composite braking is the key to realize good braking performance of electric vehicle, braking stability and higher energy recovery efficiency.This paper studied the turning stability control for the precursor of pure electric vehicles based on electro-hydraulic brake system of EHB, the main work is as follows:(1)The vehicle model established by Carsim.The magic tire model based on tire loading and road adhesion coefficient and permanent magent brushless motor model was established by Simulink. The parameters of braking system was identified through the test data, then modeling the electric hydraulic system based on these identification parameters.(2)The load transferring under the composite condition of turning and braking was analysis by simulation, and the maximum braking force was determined by dynamic loading. The fuzzy-PID controller based on the yaw velocity has been designed. Through differential braking model, the vehicle stability was realized. The strategy of braking distribution based on the elcetro-hydraulic braking system of ront axle driving electric vehicle has been designed. The different braking model switching stability problem has been analysis, and solved by motor force compensation. The validity of the control strategy was certificated by simulation.(3)In order to realize the braking system response requirement and the braking force precision control, the experiment plan of electric hydraulic braking system was designed.According to the experiment plan, the control programming has been wrote. The high-speed on-off valve dynamic characteristic was researched by testing. Established the steady pressure changing MAP.It described the steady pressure changing as the duty ratio and the initial pressure changing.According to this, the programming of closed-loop pressure adjusting has been wrote. The wheel cylinder pressure effectively followed the braking pedal signal was realized. Through the test, the braking system response requirement and the braking force precision control was certificated. |
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