Cyclic time averaging for machine monitoring

Abstract

A cyclic time averaging method is directed at processing time-domain vibration data of the machine to produce an averaged time waveform over a selected cyclic time period. It is not necessary to employ a triggering signal to obtain the averaged time waveform.

1 . A system for analyzing vibration data, said system comprising: 
 an input port configured to receive a plurality of vibration amplitude samples taken at discrete sampling times;    a first module configured to estimate vibration amplitudes at times between at least one pair of adjacent discrete sampling times;    a second module configured to use said estimated vibration amplitudes in performing a cyclic average.    
   
   
       2 . The system of  claim 1 , wherein said first module comprises an interpolator.  
   
   
       3 . The system of  claim 2 , wherein said vibration amplitude samples are taken from a machine having a characteristic repeated cyclic phenomena recurring over a period M.  
   
   
       4 . The system of  claim 3 , wherein adjacent discrete sampling times are separated by a time period of 1/F s , where F s  is a sampling frequency, and wherein period M=(n+α)/F s , wherein n is an integer, and α is a number between 0 and 1.  
   
   
       5 . The system of  claim 3 , wherein said second module comprises an averager configured to produce an average vibration amplitude by computing the average of a first sampled value at time p and the sampled or interpolated vibration amplitude value at one or more later times p+m(n+α), where m is an integer, wherein n is an integer, and α is a number between 0 and 1.  
   
   
       6 . The system of  claim 1 , wherein said second module is configured to perform the cyclic average independent of a trigger signal.