Analysis Method Of Rotating Machine's Vibration Signals Based On Cyclostationary Property

When the rotatary speed fluctuates randomly, the vibration signals of rotating machine(such as automobile engine, positive speed gear box) vary with randomly fluctuating frequency, which have the property of non-stationarity. The existing analysis methods, such as Fourier Transform and order analysis, cannot express the property of these signals accurately. In order to analyze and process these signals accurately, this paper has chiefly done the research in the following aspects:(1) The rotatary speed of single-phase asynchronous machine of JZ5622 is measured. Through preliminary statistics, it is found that the fluctuation discipline of the speed conforms to normal distribution under certain circumstances.(2) The simulation sampling of signals with normal random fluctuation is done by means of uniform time sampling and uniform angle sampling, the results of which show that: the uniform angle sampling difficult to realize can be replaced by uniform time sampling if the sampling rate is high enough.(3) The cyclostationary property of random angle signal due to angular speed fluctuation of rotating machine is theoretically proved, which provides the theoretical basis for the consequent new spectrum analysis method.(4) On the basis of order analysis theory, rotating spectrum is put forward, which is used to analyze the uniform angle acceleration signals due to the unbalance mass of the single-phase asynchronous machine of JZ5622. It achieves better results than others obtained by existing methods.The unbalance mass of the single-phase asynchronous machine of JZ5622 is correctly predicted by the rotating spectrum, which primarily shows the reliability of this method. Theory of cyclostationary signals of rotating machine vibration and the rotating spectrum aiming at these signals enrich the achievements of the signal analysis and processing.