Method and apparatus for in-situ detection and isolation of aircraft engine faults

A computer program product for enabling a computer to implement operations for performing a fault estimation based on a plurality of residuals of a plurality of detected signals, the computer program product comprising a computer readable medium and instructions on the computer readable medium, the operations comprising:

• determining an operating regime based on a plurality of parameters;
• extracting predetermined noise standard deviations of said residuals corresponding to said operating regime and scaling said residuals;
• calculating a magnitude of a measurement vector of said scaled residuals and comparing said magnitude to a decision threshold value;
• extracting a mean direction and a fault level mapping for each of a plurality of fault types, based on said operating regime;
• calculating a projection of said measurement vector onto said mean direction of each of said plurality of fault types;
• determining a fault type based on a maximum projection of said measurement vector onto said mean direction of each of said plurality of fault types;
• and
• mapping said projection to a continuous-valued fault level using a lookup table.

A method for detecting and isolating faults in a system, comprising:

• detecting a plurality of signals;
• determining a residual of each of said plurality of signals;
• determining an operating regime based on a plurality of parameters;
• extracting predetermined noise standard deviations of said residuals corresponding to said operating regime and scaling said residuals;
• calculating a magnitude of a measurement vector of said scaled residuals and comparing said magnitude to a decision threshold value;
• extracting a mean direction and a fault level mapping for each of a plurality of fault types, based on said operating regime;
• calculating a projection of said measurement vector onto said mean direction of each of said plurality of fault types;
• determining a fault type based on a maximum projection of said measurement vector onto said mean direction of each of said plurality of fault types;
• and
• mapping said projection to a continuous-valued fault level using a lookup table.

An apparatus for detecting and isolating faults in a system based on a plurality of residuals of a plurality of detected signals, said apparatus comprising:

• a processor configured to determine an operating regime based on a plurality of parameters;
• extract predetermined noise standard deviations of said residuals corresponding to said operating regime and scale said residuals;
• calculate a magnitude of a measurement vector of said scaled residuals and compare said magnitude to a decision threshold value;
• extract a mean direction and a fault level mapping for each of a plurality of fault types, based on said operating regime;
• calculate a projection of said measurement vector onto said mean direction of each of said plurality of fault types;
• determine a fault type based on a maximum projection of said measurement vector onto said mean direction of each of said plurality of fault types;
• and map said projection to a continuous-valued fault level using a lookup table.

A system for detecting and isolating faults based on a plurality of residuals of a plurality of detected signals, said system comprising:

• a detector which detects said detected signals;
• an extended Kalman filter which compares said detected signals with estimates of said detected signals and outputs a plurality of residuals;
• and
• a processor which performs hypothesis testing on said residuals to determine a fault type and a fault level.