Simplified Machine Diagnosis Techniques in Absolute Deterioration Factor by Using the 2nd Order AR Model

Abstract

In order to make machine diagnosis, the method of calculating Kurtosis or Bicoherence was utilized. Calculating system parameter distance was also utilized applying time series data to Autoregressive (AR) model or Autoregressive Moving Average (ARMA) model.

In this paper, simplified calculation method of autocorrelation function is introduced and it is utilized for the 2nd order AR model identification. An absolute deterioration factor such as Bicoherence is also introduced. Furthermore, Mahalanobis’ generalized distance is introduced by the relationship with system parameter distance. Three cases in which the rolling elements number is nine, twelve and sixteen are examined and compared. Machine diagnosis can be executed by this simplified calculation method of system parameter distance. Good results are obtained.