A Model-Based Approach For Aeroengine Performance Deterioration Mitigating Control

Turbofan engine is one of the most important power plants for plane. The engine control capability determines the flying quality and reliability, among which performance deterioration mitigating control(PDMC) has been paid widespread attention. The key technologies of PDMC include engine modeling and component characteristic correction, and mixed iterative learning control are studied in this thesis, and simulations are carried out to certify the PDMC for turbofan engine.A nonlinear component-level performance model of the turbofan engine was built up. In order to decrease the modeling error between turbofan engine mathematical model outputs and its test data, a method to correct the component characteristics using PSO algorithm is introduced. The digital simulation results show that the correction of fan and compressor simultaneously could improve the accuracy of mathematical model.Aeroengine performance deterioration is inevitable during its life cycle, a self-tuning on-board model based on linear parameter varying modeling is presented to obtain engine performance change. Impulses to multiple health parameters deteriorate simultaneously is discussed to build up the state variable model(SVM). On the basis of the SVM, the LPV modeling approaches is given by using the elements and eigenvalue of coefficient matrix as an index variable respectively. The LPV model is corrected by baseline adjusting at the steady state, and by Kalman filter in the transient process. The accuracy of LPV model is improved and the performance deterioration of engine could be estimated.The approach to estimate the engine thrust is also introduced in the paper, and a model based thrust estimator is designed. The mixed controller is then designed by the iterative learning control algorithm combined with the PID control method, and the simulator of aircraft engine performance deterioration mitigating control is constructed using Matlab Simulink. The integrated simulations under several performance degradation cases show that the PDMC could tune the thrust to acquire a satisfactory value, and it avoids the plane yaw.