Model-Based Fault Diagnosis Of The Anti-lock Braking System

Anti-lock braking system(ABS)is an automobile safety system that allows the wheels on a motor vehicle to maintain tractive contact with the road surface according to driver inputs while braking,preventing the wheels from locking up and avoiding uncontrolled skidding.Its functionality and reliability will directly affect the safe driving of the car.Therefore,research on the fault diagnosis technology of ABS can fully evaluate the working status of ABS,quickly diagnose the fault,and make it possible to predict the possible potential faults,which is important for improving the safety and reliability of the vehicle and has great theoretical and practical value.This paper introduces a model-based structural analysis method(SA)fault diagnosis theory to analyze ABS faults,and designs robust residuals to verify the effectiveness of fault diagnosis theory based on structural analysis.Specific studies include:Firstly,based on the basic structure and function of the ABS system,all faults of the ABS are analyzed and evaluated using the failure mode,Failure Mode,Effects and Criticality Analysis(FMECA)technology to obtain its critical faults.Firstly,the failure mode and influence analysis(FMEA)method are used to summarize the fault modes,fault effects and fault causes of ABS system.The fault severity level and fault probability of each fault are studied,and then the criticality matrix of ABS is drawn.The graph performs a criticality analysis(CA)on the system,resulting critical faults of the ABS.Secondly,based on the existing mature ABS system mathematical model and vehicle dynamics model,using the acquired ABS critical faults,and parameterizing these critical faults to establish the initial fault model of the ABS system;using the structural analysis method fault diagnosis theory,DM decomposition is performed on the ABS initial model to analyze the detectability(FD)and isolability(FI)of the ABS initial model for critical faults;in order to improve the fault diagnosis capability,the configuration scheme of ABS sensors is studied,and the design of the ABS sensor is designed.Various types of sensor configuration schemes are repeatedly decomposed by DM to obtain the detectability and isolability capability of the fault,and an optimal sensor configuration scheme is obtained.Finally,the ABS initial fault model was optimized and a new model was obtained.The SA is used for fault diagnosis analysis to obtain the FD and FI results of the system.Using the structure MSO sets,four groups of residuals are generated to complete the FDI system design,and an FDI simulation model of ABS is established in Simulink,by setting four key failure types and occurrence times,and a fixed threshold.Whether the residual error exceeds the set threshold is a judgment condition to judge whether the fault occurred.The diagnostic results are compared with the pre-set faults to verify the feasibility and effectiveness of the fault diagnosis system based on the structural analysis method on ABS.