Analysis of rotating machines

Abstract

System and method for analyzing an input signal acquired from a physical system with a rotating element. A tachometer signal is received comprising rotation speed information for the rotating element. A time sequence is determined using the tachometer signal, comprising time values for the rotating element at substantially equal angle increments, e.g., by edge detection software or timer / counter. A software-based first digital interpolation filter, e.g., a Cascade-Integrator-Comb filter, is applied to the time sequence, generating a modified time sequence. A digitized data signal is received comprising data for the rotating element at substantially equal time increments. A second software-based digital interpolation filter is applied to the data signal, generating a modified data signal which is re-sampled using the modified time sequence to generate an angle domain data signal, comprising data signal values at substantially equal angle increments, where the angle domain data signal is usable to analyze the physical system.

Description

[0001] The invention relates generally to signal analysis systems or test and measurement systems, and more particularly to a computer-based system and method for analyzing order components of a signal generated by a physical system, e.g., a mechanical system containing one or more rotating elements.DESCRIPTION OF THE RELATED ART[0002] Scientists and engineers often use test and measurement systems and data acquisition systems to perform a variety of functions, including laboratory research, process monitoring and control, data logging, analytical chemistry, test and analysis of physical phenomena and analysis or control of mechanical or electrical machinery, to name a few examples. One example of hardware to implement such measuring systems is a computer-based measurement system or data acquisition (DAQ) system. Another example of a measurement system is a dedicated instrument, such as a dedicated oscilloscope or signal analyzer.[0003] A measurement system typically may include tra...

AI Technical Summary

Problems solved by technology

The frequency smearing makes it very difficult to derive meaningful information about the order components.

Thus, traditional signal analysis methods such as the Fourier Transform of the time domain input signal are not well suited for analyzing order components generated by rotating machines.

However, this approach may result in discontinuities at boundaries of the polynomial pieces or segments.

In other words, the tracking performance is likely to be degraded when an inaccurate signal model is supplied to the filter.

Furthermore, the Vold-Kalman filter provides no mechanism for the user to evaluate the accuracy of the frequency tracking for an order component.

However, this approach may cause discontinuities at the boundaries of each polynomial segment or piece.

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