Engine Monitoring Based on Normalized Vibration Spectra

An electronic engine-health-monitoring system is based on (1) computation of frequency-phase-normalized (FPN) spectra from the digitized outputs of vibration sensors and (2) the use of these spectra as feature vectors, which are presented to an artificial neural network for recognition of features associated with incipient failures. The normalization in question is with respect to the instantaneous frequency and phase of rotation of the engine shaft [customarily denoted the "sync" (short for "synchronous") frequency and phase, respectively]. FPN spectra are useful for extracting that dynamical information that is most useful for detection and classification of failures.