Vibration data processor and processing method

• US 6,633,822 B2
• Filed: 07/23/2001
• Issued: 10/14/2003
• Est. Priority Date: 07/29/1997
• Status: Expired due to Term

• Current Assignee: SKF USA Incorporated (SKF)
• Original Assignee: SKF Condition Monitoring Inc
• Inventors: Boerhout, Johannes I., Maness, Philip L.
• Primary Examiner(s): ASSOUAD, PATRICK J
• Application Number:
  US09/912,224
• Publication Number:
  US 20020038187A1
• Time in Patent Office: 813 Days
• Field of Search: 702/56, 702/34, 702/35, 702/36, 702/39, 702/183, 702/184, 702/185, 702/77, 708/300, 708/303, 708/400, 708/404, 708/406
• US Class Current: 702/56
• CPC Class Codes: G01M 13/045 Acoustic or vibration analysis
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/2696 Wheels, Gears, Bearings
• CPC Class Codes: G01N 29/12 by measuring frequency or resonance of acoustic waves measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00
• CPC Class Codes: G01N 29/42 by frequency filtering or by tuning to resonant frequency
• CPC Class Codes: G01N 29/46 by spectral analysis, e.g. Fourier analysis or wavelet analysis spectral signal processing per se G06F17/14

Abstract

A vibration data processor and processing method uses a frequency domain filter having low pipeline delay and accurate time domain signal reconstruction. The filter may be user configurable, and the filter may receive input data from a variable number of decimation stages. Sequences of extracted vibrational features are routed to a variable length output buffer for event detection.

Claims

1. A vibration monitoring system comprising a digital filter having a time domain input coupled to an output of an analog to digital converter and a time domain output coupled to an input of event detection circuitry, wherein said filter has a pipeline delay of less than approximately 100 milliseconds.

2. The vibration monitoring system of claim 1, wherein said digital filter is implemented with a single chip digital signal processor having a maximum throughput of less than approximately 10,000,000 computations per second per channel, and wherein each channel is sampled at a rate of least approximately 25.6 kHz.

3. The vibration monitoring system of claim 2, wherein said digital filter comprises a frequency domain filter.

4. A vibration data processor, comprising:

a frequency domain filter for filtering digital samples of a vibration transducer signal;

a mask generator coupled to said frequency domain filter for creating and storing filter masks used by said frequency domain filter.

5. The vibration data processor of claim 4, additionally comprising a user input device coupled to said mask generator for user specification of one or more frequency response characteristics of said frequency domain filter.

6. The vibration data processor of claim 4, additionally comprising a digital pre-processor configured to receive time domain data samples, and coupled to said frequency domain filter so as to forward pre-processed time domain data samples to said frequency domain filter.

7. The vibration data processor of claim 6, wherein said pre-processor comprises a plurality of decimation stages.

8. The vibration data processor of claim 7, additionally comprising a user input device coupled to said pre-processor so as to select a subset of said plurality of decimation stages for operation.

9. A method of analyzing vibration data comprising the steps of:

selecting a size of a data accumulator;

storing measured vibrational features in said accumulator;

when said accumulator is full, updating the content of an output buffer with the content of said accumulator; and

calculating overall vibration parameters using the content of said output buffer.

10. The method of claim 9, additionally comprising the step of selecting a size of said output buffer such that said size is an integer multiple of said size of said accumulator.

11. A vibration data processor comprising an output buffer of user selectable length and an accumulator of user selectable depth, wherein said accumulator receives vibrational data at first intervals from the output of a digital vibration data filter, wherein said accumulator stores said data, a maximum amount of data storable therein being defined by said user selectable depth;

and wherein said accumulator is coupled to said output buffer so as to periodically update said output buffer at second intervals when said accumulator is full.

12. The vibration data processor of claim 11, wherein said digital vibration data filter comprises a frequency domain filter.

13. A vibration data processor, comprising:

a pre-processor comprising a user selectable number of decimation stages;

a user configurable frequency domain filter coupled to receive data from said pre-processor; and

an output buffer of user selectable length coupled to receive vibration data from said frequency domain filter.

14. The vibration data processor of claim 13, additionally comprising a feature extractor coupled between said frequency domain filter and said output buffer.

15. The vibration data processor of claim 14, additionally comprising an accumulator of user selectable depth coupled between said feature extractor and said output buffer.