Study On Multiple LPV Model Switching Method And Safety Protection For Turbofan Aeroengines

In the modern national defense and civil field,an aircraft is a weapon of national defense and a means of life.Aircraft engines,as the main component of aircrafts,have great value to be researched.The performance of an aircraft engine affects the performance directly of the aircraft.With the structure of aero-engine becoming more and more complex,the requirement of excellent control methods is higher and higher.Based on the operation data of a turbofan engine and the simulating,it proves that the diffferent scheduling methods of linear parameter varying system have different effects on the performance of the open or closed loop system of the engine,and then based on the analysis of simulation,the switching rule of scheduling methods is designed to improve the dynamic performances of aircraft engine.Finally,the multi loop safety protection controller and corresponding switching rules of aero engine are designed,which are used for ultra high speed control of aero engine and protect its flight safety.The main works of this paper includes:First of all,based on the operation data of a turbofan engine and used the methods of interpolation the model of LPV is given,and then we designed a state feedback controller of the LPV model of different scheduling methods.The model precision of LPV model of aero engine,under different scheduling modes,is studied.We established the LPV model with the different scheduling variable of rotor speeds of a turbofan engine,Simultaneously,through the simulation and analysis of the internal structure characteristics of the aeroengine,the different selection of scheduling variables of the LPV model,it has different influence in open loop system.Then,we designed different state feedback controllers,using different scheduling variables,and studied the different influence on the performance of the closed-loop system under different scheduling methods.The simulation shows that when the scheduling variable is the high pressure rotor speed,the response of speed of the closed-loop system is faster,but it has overshoot;when the scheduling variable is the low pressure rotor speed,the response of speed of the closed-loop system is lower but it has small overshoot or no overshoot.Secondly,according to the above research results,the switching rules for multiple controllers based on different schedulings and LPV models are given.And a method of scheduling mode switching is designed,which makes the aero-engine not only have faster speed response,but also achieve small overshoot,It ensures the stable and fast operation of the aero-engine.Finally,we carried out relevant research on the multi loop safety protection of aero engine.And we designed the corresponding safety controllers for the high rotor speed and the outlet temperature of the aero-engine,and then designed the corresponding safety protection switching rules,and switching and tracking based on the corresponding design,safety protection switching rules,and at the same time,for aero engine overspeed and overtemperature condition,we designed the switching rule based on the margin of safety of aero engine.The designed controller and the corresponding switching rules can ensure the safe operation of the aero-engine.