Fault Tolerant Control Of Aircraft Engine Control System Based On Sliding Mode Theory

Aircraft engines are very complex systems with high degree of nonlinear character,and the working state of the engine is very large in flight envelope.Therefore,the occurrence of the control system failure is inevitable,sensor fault in particular.Accordingly,based on sliding mode theory,fault diagnosis and fault tolerant control of aircraft engine control system is studied in this thesis,which is of great significance to improve the safety and reliability of engine control system.In this thesis,the main contents included: the establishment of aircraft engine linear state space model based on the fitting method,the design of aircraft engine fault diagnosis system,and the design of aircraft engine fault tolerant control system.Firstly,a linear state space model for Aircraft engine component level model based on fitting method is presented in this thesis at first.Secondly,based on the state space model,a fault diagnosis system of aircraft engine sensor based on residual is designed and two kinds of fault diagnosis methods based on residuals are compared and analyzed.Finally,the state space model of a turbofan engine is taken as an example,and the effectiveness of the method is verified by digital simulation based on the residual fault diagnosis method.Secondly,considering the engine of uncertain model,this thesis puts forward a new method of aircraft engine fault tolerant control of a sliding mode adaptive fuzzy integral tangent in this thesis.Based on the fault diagnosis of sliding mode observer,fault tolerant control system for aircraft engine is designed.The state space model of a turbofan engine is taken as an example,the simulation results show that the method can effectively prevent integral saturation phenomenon,reduces the steady-state error of the system,improve the transient performance,has strong robustness and fault tolerance has good control ability of the control system.Thirdly,considering how to adjust the closed-loop response of aircraft engine system,this thesis proposes a new method for fault tolerant control of sliding mode tracking with integral function.Based on the fault diagnosis of the Kalman filter,fault tolerant control system for aircraft engine is designed.The state space model of a turbofan engine is taken as an example,the simulation results show that this method can improve the performance of the engine closed-loop response without sacrificing the steady-state accuracy of the aircraft engine system,and has a good fault tolerant control capability.