Method for diagnosing performance degradation of machine element, and system for same

A system for diagnosing performance degradation of a machine element comprising:

• an Acoustic Emission (AE) sensor that is mounted on the machine element serving as a diagnosis target and that generates an Acoustic Emission (AE) waveform signal representing an elastic wave occurring inside the machine element;
• a vibration sensor that is mounted on the machine element and that generates an acceleration signal based on a vibration wave occurring inside the machine element;
• a signal processing unit that comprises
• an Acoustic Emission (AE) signal processing system that detects a state change occurring inside the machine element in an Acoustic Emission (AE) method using a plurality of the AE waveform signals chronologically occurring by receiving the plurality of AE waveform signals and performing predetermined signal processing on the plurality of AE waveform signals,
• a vibration signal processing system that detects the state change in a vibration method using the acceleration signal by receiving the acceleration signal and performing predetermined signal processing on the acceleration signal, and
• a switching parameter generating section that generates a predetermined numeric parameter to switch a measuring mode from the AE method to the vibration method;
• and
• a controlling unit that selects a result of processing in the AE method performed by the AE signal processing system at an initial stage and selects, after the numeric parameter turns from increasing to decreasing as time passes, a result of processing in the vibration method.