Energy-Based Switching Control For Aero-Engine And Research On Scheduling Mode

It is of great value to conduct the research of an aero-engine,which is the main part of an aircraft.With the structure of aero-engine becomes more and more complicated,the requirements of control system are greatly improved.In this thesis,a turbofan engine is used as the research object.We study the speed control of aero-engine by two methods which are the energy-based switching and scheduling mode switching.A switched controller is designed using the real-time data of the component level model,where the switching law depends on the Mach number related system energy.Then the LPV model of aero-engine is established by interpolating and fitting,and the H? controller is designed based on the different scheduling modes.The influence of scheduling mode on the performance of engine is analyzed,and the dynamic performance of aero-engine is improved by using the idea of switching system.The main contents can be stated as follows:First of all,this thesis studies the speed regulation problem of a two-spool turbofan engine working in multi-Mach.A switched controller is designed using the real-time data of the component level model,where the switching law depends on the Mach number related system energy.Overshoot-free speed regulation and safety issues are ensured by the proposed controller.Moreover,a scheduling variable is given to enhance the control performance in the presence of abrupt changes of Mach number.The result in this thesis is not only validated by simulation but also guaranteed by theory.The simulation result on the CL model has proven the effectiveness of proposed approach.Secondly,we study the scheduling mode of LPV model for aero-engine.Based on the LPV model,the rotor speed of turbofan engine is regarded as a scheduling variable.The rules of scheduling modes are analyzed by simulation and analysis from the structure of the aero-engine.The higher the variation of the variable,the higher the steady-state error.Then the H? output feedback controller is designed to study the influence of different scheduling modes on the whole closed-loop system.The simulation results show that in the LPV system of the aero-engine,the change rate of scheduling variable affects the rate of the system response.The faster(slower)the scheduling variable changes,the faster(slower)the response turns,and the greater(smaller)the overshoot is.Finally,we propose a method to switch the scheduling variable based on the above discussion and simulation results so that the aero-engine has not only a fast response speed but also generates little or no overshoot.The simulation result has proven the effectiveness of proposed approach.