The Faults Simulation And Experimental Research Of Automobile ABS System

The safety problem gets more and more attention with the development of the automobile industry and the rapid increase of the driving speed.The faults of the ABS are related directly to the safety of vehicles and drivers as an active safety system.This article is mainly about the simulation and experimental research on the faults of the ABS system which can not be identified in the self-examination.Firstly,it elaborates the background and significance of the study,introduces the current research about the ABS system faults.Then it introduces the structure of the ABS system,and describes the working principle of it according to the four operating modes: the conventional brake pattern,holding pattern,pressure reducing pattern and pressure increasing pattern.It describes the braking process according to the coefficient of road adhesion and the slip ratio,then analyzes several common control algorithms.On this basis,combined with the logic threshold control theory under the environment of MATLAB/Simulink,it sets up the 1/4 dynamics model of a vehicle based on the logic threshold control theory.The theories are described and the simulation model are set up with the slip ratio model,the road surface model and the hydraulic system model of the ABS,and gets the work process of several road,such as the dry asphalt,the dry gravel,the snow,etc.All parameters are analyzed about the braking distance,slip rate and the braking torque,etc,which can reflect the working principle of the ABS system.It describes the four faults which can not detect in the self-examination of the ABS system,including the wheel speed sensor fault,the oil leakage fault,the valve clamping and the loss fault of the plunger pump performance efficiency.On the basis of the structure of the simulation model,it builds each fault model,and gets some braking torque curve of various failures by simulation,then builds a database of failures.In order to verify the results of these simulations by experiment,it designed and developed the test platform for autonomous control of the ABS system based on dSPACE,and the test platform successfully drives the valve for continuous acting according to some instruction given.At the same time,it establishes the data collecting system to collect the vibration signal and the voice signal.It contrasted the voice signals and vibration signals,and the voice signals and the braking torque for analysis,and it can be concluded that the vibration signals and voice signals can correspond with the process of the valve’s acting in time.Therefore,it can reflect the mechanical movement of the valve by the characteristic parameters by the process of extracting and analyzing of voice signals or vibration signals,and it can detect the faults of the ABS system by monitoring the characteristic parameters.