Research On Fault Diagnosis And Fault-tolerant Control Of ESP Based On Analytical Redundancy

Automotive Electronic Stability Program (ESP) based on Anti-lock BrakingSystem (ABS) and the Traction Control System (TCS), can improve the handling andstability of vehicle, which belongs to the automobile active safety. It consists of thesensors to collect necessary signals, the electronic control unit (ECU) to calculate andactuators to apply the brake which the ECU wants. The decision of ECU depends onthe signals from the sensors. Once a sensor fails, the ECU will receive an error signaland make the wrong instruction, which makes ESP seriously threat the security ofautomobile. Therefore, one of the basic structure of the sensors is on-line monitoringsystem for early fault diagnosis, to avoid the occurrence of danger. Once sensor faultis confirmed from diagnosis, automobile ESP system will stop working to avoid falseintervention. This is early thoughts for the ESP fault-tolerant system. Now, a popularresearch direction is ESP fault-tolerant control to make use of ESP remainingavailable function after some fault detected from sensors.This article concerns the analytical redundancy in ESP and its value on faultdiagnosis and fault tolerant control for ESP system. Therefore, MATLAB/Simulinkand Carsim software are used to set up a complete model of the automobile ESPsystems, including the Electro-Mechanical Brake (EMB) actuator model, model ofvehicle dynamics models and ESP control strategy. With the model, we worked on thestudy on the analytical redundancy of yaw rate sensor and lateral accelerometer sensorand steering wheel angle sensor signal, taking into account the conditions of theirvalidity, and modeling and simulation to test the reliability of analytical redundancymodel. With the model of analytical redundancy, automobile ESP system isimplemented in the yaw rate sensor and lateral accelerometer and steering wheelangle sensor failure diagnosis based on a calculation of residual signals and methodfor determining the dynamic threshold. After determining the sensor fault diagnosismethod and specializes in building estimated from a valid model of analyticalredundancy compensation signal, fault sensor signals will be isolated and replaced by compensation signals to achieve fault-tolerant control for automobile ESP systems.When estimating compensation signal is unreliable or the signal is unable to becalculated, ESP system will be shut down. The research has achieved some desiredeffect.