Research Pressure Model Algorithm Of Vehicle ESC Accurate Control

With the continuous development of automotive technology, more and more people begin to pay close attention to active safety systems, Vehicle electronic stability control ESC as the important active safety technology products become the focus of major car manufacturers developed. ESC systems include anti-lock braking system(ABS), Traction Control System(TCS) and active yaw control(AYC). ESC system make the vehicle in a stable state mainly by reducing the engine output torque and regulating four wheel brake pressure to control the body-posture. The adjustment of the brake pressure has an important influence on control effect and ride comfort in the ESC working process.Combining with the research achievements in the field of vehicle stability control of vehicle dynamics and control group of Tsinghua University, the paper focus on solve the wheel cylinder pressure estimation problem in the ESC control process basing on the practical use. The pressure model algorithm based on accurate control of ESC is proposed. On the basis of the estimated wheel cylinder of stress model can identify the adhesion coefficient on the ground, the target pressure can be calculated in the working process of ABS and TCS. We can get the next cycle’s control commands by calculating the difference between the target pressure and the estimated pressure. The vehicle which belongs to C30 series of Great Wall Company is utilized in ESC vehicle test, to verify the accuracy of the model between the active increase pressure and passive increase pressure.ESC hydraulic control unit as the study object of this paper, to analysis the internal workings principle of ESC. Based on theoretical analysis, the mathematical model of each component in the HCU is established and the AMESim simulation model is built. Through theoretical analysis and simulation data analysis, we can obtain the delay characteristics and the flow characteristics of the solenoid valve. The pressure model is built through theoretical analysis and observation wheel speed, according to the practical application problems, the method of use Kalman filter observation wheel pressure is proposed. Estimation pressure may be corrected in accordance with the movement of wheel, and the method can reduce the requirement of the theoretical model. According to the real vehicle test verification, the pressure model can be used to apply the actual control program. The road adhesion can be quickly and accurately identified based on the wheel cylinder pressure, and it has an important meaning to optimize the ESC control program.