An alternative time-domain index for condition monitoring of rolling element bearings—A comparison study

Statistical moments have been widely used for detection and diagnosis of rolling element bearing damage. Among them, Kurtosis and Honarvar third moment S_r are the major parameters. In this paper a new statistical moment, from the viewpoint of Rényi entropy, is derived, which is shown to be as effective as kurtosis and S_r. Comprehensive comparisons of kurtosis, S_r and this moment are performed, and the results from simulations and experiments show the new moment has a better overall performance than kurtosis and S_r. On the one hand, this moment behaves much like kurtosis but is less susceptible to spurious vibrations, which is considered to be one of the main shortcomings of higher statistical moments including kurtosis. On the other hand, from the viewpoint of sensitivity to incipient faults, which is the major drawback of lower statistical moments including S_r, the new moment is superior to S_r. Moreover, the sensitivity of this new moment to changes of bearing speed and load is also less than kurtosis and is close to that of S_r.