Research On Active Fault-tolerant Control Of Aero-engine Control System

Aero-engine has been working in the harsh environment of high temperature,high pressure and strong vibration for a long period of time.The actuator and sensor of its control system become the sensitive and the most possible fault-occurring location,which affects the safety of the whole aero-engine seriously.Therefore,the research on fault estimation and fault-tolerant control for actuator and sensor faults,has a great engineering significance to ensure the reliability of the control system.The main contents of this paper include:Firstly,the small perturbation state variable model of aero-engine is established by least square method and the fitting method.On this basis,the linear-parameter-varying(LPV)model in the form of affine parameter dependence is established by the matrix pseudo inverse method.When the actuator and sensor of aero-engine control system have faults,the approach of fault estimate and fault-tolerant control should be proposed quickly to ensure the system can still work.Then,a robust adaptive fault estimation observer and an LPV fault estimator based on linear fractional transformation(LFT)are proposed.Firstly,for the aero-engine LPV model with actuator multiplicative fault under disturbances,a robust adaptive fault estimation algorithm is proposed to solve the problem of the aero-engine with actuator multiplicative fault under external disturbances.After that,for the problem of the aero-engine with both actuator and sensor additive fault under disturbances,an LPV fault estimator with scheduling characteristics is designed by using bounded real lemma and projected theorem.Simulation results show that the proposed method can obtain failure information accurately.Furthermore,according to the results of fault estimator,an active fault-tolerant control method based on virtual actuator is proposed for aero-engine fault system with multiplicative and additive faults of actuator under disturbances.Without changing the parameters of the error feedback controller,the reconfiguration strategy is constructed by error feedback controller,virtual actuator and error interval observer.Simulation results show that the performance index of the reconstructed system is similar to the fault-free system,and the active fault-tolerant control for the aero-engine control system of actuator is achieved.Finally,aiming at the aero-engine fault system with multiplicative and additive faults of actuator and sensor under disturbances,an active fault-tolerant control method based on virtual actuator and virtual sensor is proposed on the basis of the fault estimator results.Under the condition of not changing the parameters of the error feedback controller,the reconfiguration strategy of the aero-engine fault system is constructed by error feedbackcontroller,virtual actuator,virtual sensor and error interval observer.Simulation results show that the reconstructed system can make the performance similar to the fault-free system,and achieve the active fault-tolerant control for the aero-engine control system of the actuator and sensor.