Research On Data-Based And Multiple Model-Based Method For Fault Diagnosis Of Engines Control System

Aeroengine has the characteristics of high complexity and high precision,which becomes the research focus of aeronautics and astronautics field.Engines work in the environment of high temperature,high speed and high load for a long time,the probability of failure occurs will greatly increase,and cause huge property damage and casualties.With the application of control system in industry and military fields,the fault diagnosis method based on analytic redundancy can effectively and quickly detect the fault of the system,which has significant theoretical research and practical application value.Aiming at the fault diagnosis of aeroengine control system,the thesis adopts data-driven algorithm and multiple model method to realize the detection and isolation of system fault.Adaptive dynamic programming(ADP)is selected as the basic iterative algorithm for fault diagnosis in the first place.ADP method is applied to the optimal control problem of nonlinear system,which can obtain the optimal control law by approximating and solving the HJB equation of the system.In the thesis,the ADP method is applied to the fault diagnosis problem,which is suitable for the system with strong nonlinearity and high complexity and overcomes the shortcomings of other algorithms.The engine data and multiple models of the research are given at the same time.In the thesis,a fault diagnosis method based on ADP iterative algorithm for the actuator fault of the engine is proposed,and the stability and convergence proof of the algorithm are given.The algorithm does not need the exact analytic model of the system,and eliminates the interference of system drift and input dynamic uncertainty to the fault diagnosis result.Working modes of the system are selected,and the effect of data jitter of mode switching on the fault diagnosis is eliminated by using multiple model method.Then,several common failure models of engine are introduced,and fault detection and isolation results of multi-faults occur simultaneously.At last,a Matlab simulation result is given to verify the proposed fault diagnosis algorithm.A turbo-fan engine was selected as the object of research,and the servo signal is used to avoid the introduction of noise and reduce damage to the system.Through the program,the HJB equation of the system is approximated and iterated and system's working modes are represented by data,to achieve the detection and quantification of fault so that the fault can be isolated.The experimental results show that the proposed algorithm work,and can be applied to the engine control system with strong nonlinearity.