Application of the ARMA model in non-stationary vibration signals

In order to process the non-stationary vibration signals such as speed up or speed down, a new method combined computed order tracking method with the ARMA model analysis to analyze the instantaneously signals in the rotate mechanism is explored. Firstly, the vibration signals at start-up in the gearbox are sampled at constant time increments in time-domain, and then the data are to resampled with software at constant angle increments in angle-domain. Therefore, the non-stationary signals in time-domain were changed into stationary ones in angle-domain. At last the stationary ones are analyzed with the ARMA model. The outcome shows it can avoid effectively the “frequency smear” phenomenon with order tracking technology, which cannot be solved with the traditional frequency spectrum method. The disturbances of non-Gaussian signals are avoided with the ARMA model. The instantaneously signals during the rotate mechanism can be analyzed accurately with the method, which combined the order tracking with ARMA model, and the method has more amplitude appliance foreground.