Research On Rapid Prototyping Platform For Aero-Engine Gas Path Health Diagnosis

Gas path health diagnostic technology is an important way to achieve stable aero-engine operation,reduce engine maintenance costs,and improve aircraft flight safety.The traditional aero-engine health management system has problems of high cost and long development cycle.The rapid prototyping method has provided an efficient way for developing the system and a new way to verify the application prospects of the system.In this paper,the method of estimating the health parameters of aero-engine gas path based on the reaching law sliding mode observer is studied.A rapid prototying platform is designed to verify the aero-engine gas path health management system.Aiming at the modeling uncertainty and system disturbance of turbofan aero-engine,the reachching law sliding mode observer is designed for aero-engine gas path state estimation.A matrix transformation is introduced to increase one-dimension analog output based on the engine system equation,so that the number of output signals exceeds the number of health parameters to be estimated,which makes robust state estimation possible.The gas path health parameters are introduced into the aero-engine system equations as unknown inputs.The reaching law is intergrated into the traditional sliding mode observer to inhibit the high frenquency chattering after reaching the sliding surface.The health parameters are reconstructed based on the equivalent output error injection signal,a scaling matrix is introduced to minimize the impact of modeling uncertainty and system disturbance on fault diagnosis.The reaching law sliding mode observer is designed by using liner matrix inequality toolbox.The accessibility and stability of the reaching law sliding mode observer are proved by using Lyapunov stability theory.The digital simulation verifications are carried out under six gas path failure modes.The functional and performance requirements of the rapid prototyping platform for aero-engine gas path health diagnosis are analyzed,the platform development process and hardware construction plan are designed in this paper.Based on the standard modular hardware produced by National Instrument,an aero-engine simulator is developed by using a NI-PXIe,a signal simulation unit is developed by using a NI-cRIO,and a fault diagnosis unit is developed by using a NI-cRIO.In the LabVIEW environment which used to develop virtual instrument,the program of each component of the rapid prototyping platform is designed by using the modular programming method such as DLL library called by CLN node,package subVI and MathScript node,to implement monitoring real-time engine operating parameters,simulating real engine sensor measurement signals,and estimating health parameters of the aero-engine gas path functions.All components are connected by useing the communication methods embedded in LabVIEW to form a complete rapid prototyping platform,the platform project is created in LabVIEW.Based on the platform,the engine gas path health diagnosis algorithm of the reaching law sliding mode observer is simulated.The method of converting graphical code into general C code provided by LabVIEW is also studied,so that the algorithms developed based on rapid prototyping platform can be transplanted to other embedded hardware devices.