Research On Aero-engine Robust Adaptive Control

The system of aero-engine has serious uncertainties,nonlinearity,multivariable,and tight coupling properties,since its structure is complex and running environment is changeable.Therefore,study on the control problem for complex uncertain nonlinear systems has great significance in theory and practical applications.The adaptive control of a turbofan is the topic of this thesis.This thesis proposes an adaptive proportional-integral-derivative(PID)control scheme under the model uncertainties and a robust adaptive PI-type control scheme under the external disturbances.The main topics are:At the second part of this thesis,the working process of aero-engine is introduced.Then a nonlinear component level model of aero-engine is researched in the paper,providing the simulation platform for the controllers proposed in the later.At last,the model uncertainties of aero-engine is analyzed.In the third part of this thesis,an adaptive proportional-integral-derivative(APID)control system is developed to deal with the model uncertainties of the nonlinear systems of aero-engine.The parameters of the adaptive PID controller are online tuned by the derived adaptation laws so that this parameters would change following the variation of the system.Then a good performance will be ensured both at design point and off-design point.A fuzzy compensation controller is designed to guarantee the system's stability.In response to the problem that the parameters of the adaptive PID controller will be too large because of integral action,a reset scheme is proposed.At last,the comparative simulations between the proposed adaptive PID controller and the conventional PID controller are presented to verify the proposed control strategy have a better performance in the Matlab/Simulink environment.Different with the third part,a robust adaptive PI-type controller incorporating a fuzzy logic system and a sliding-mode controller for robust H? performance is developed,dealing with model uncertainties and external disturbances in different ways.The fuzzy logic system is used to compensate the model uncertainties.The PI-type controller with robust H?performance is developed to ensure the influence external disturbances have on the output of system is weak.At last,simulations are presented to verify the control strategy in the Matlab/Simulink environment.