| The electronic stability control system(ESP)can prevent the car from losing stability when drive on low surface or suddenly be disturbed by lateral force,so as to ensure the safety of the car.The wheel brake control of the vehicle is based on the accurate judgment of the state of the vehicle.However,the existing vehicle-mounted sensors can not obtain the key parameters such as longitudinal speed,lateral speed and side slip angle because of the technology or cost,which makes it difficult to judge the status of vehicle.How to accurately obtain the state parameters in the vehicle driving process and correctly judge the driving status of the car is the difficulty of developing ESP system.In this paper,we estimate the longitudinal speed and lateral speed of the vehicle during the operation of ESP system,and the relevant ESP control algorithm is designed and verified by simulation.Based on the classical kalman filter,a linear model of automobile kinematics is established.The longitudinal speed of vehicle in various braking conditions is estimated and compared with the actual longitudinal speed of CarSim output.Based on the UKF,the estimation algorithm of vehicle longitudinal speed and lateral speed which is not completely dependent on vehicle dynamics model and tire model is designed,and longitudinal speed and lateral speed of different adhesion coefficients are estimated.Through to the CarSim software output analysis,the fuzzy controller which does not rely on traditional two degrees of freedom vehicle model is designed in order to control the wheel brake pressure.And based on CarSim combined Matlab/Simulink software,a joint simulation of lane keeping in low adhesion coefficient pavement is carried out.The vehicle braking HIL simulation test bench based on Lab VIEW is built.Hardware drive circuit is designed for hydraulic control unit,and hydraulic control unit is tested. |
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