Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Electrical signal parameter measurement system
Reexamination Certificate
2001-06-07
2003-10-21
Hoff, Marc S. (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Electrical signal parameter measurement system
C360S025000
Reexamination Certificate
active
06636817
ABSTRACT:
FIELD OF THE INVENTION
This application relates generally to disc drives and more particularly to an enhancing mechanical frequency signature analysis.
BACKGROUND OF THE INVENTION
It is well known that vibration of parts in a disc drive can have long-term undesirable effects on the disc drive, and reduce the time until failure. In an ideal disc drive, no vibration would be produced. In practice, however, vibration occurs as a normal by-product of the interaction of mechanical forces within the disc drive. A good disc drive design is one that produces low levels of inherent vibration. Subsequent increases in vibration level indicate a change in the dynamic characteristics of the machine, often caused by a defect or deterioration of moving parts.
Modern technology has greatly simplified and improved upon vibration monitoring techniques. Sensitive accelerometers can be used in sensing vibration, and complex electronics have evolved to process the vibration data. One method of vibration analysis is “Vibration Signature Analysis,” which is most often accomplished in the frequency domain. Under this method, time-domain vibration data are converted to the frequency domain using a Fourier Transform. The unique frequency spectrum obtained is often termed the “signature” of the disc drive. A signature of a disc drive under test may be analyzed and compared to a signature for a reference disc drive. Differences in the two spectra may indicate an abnormal condition.
A common problem associated with most of the prior art monitoring equipment is that they usually require a human operator to analyze and compare the signatures. Prior art inventions lack the sophisticated electronic circuitry and data processing necessary for automatic comparison of the spectra and for rendering a decision regarding the condition of the disc drive under test, with only minimal human interface. Prior art inventions are also generally incapable of distinguishing between ball bearing frequencies and electromagnetic frequencies. Prior art inventions are not capable of identifying sources of vibration without having the disc drive disassembled to attach a transducer directly to an element that is thought to be a source of vibration. Frequently, a disc drive and its subassemblies are disassembled only to find out that the alleged source of vibration is not the source at all, resulting in wasted time and parts. Prior art devices are also incapable of extracting events, or specific sections of interest in a typical vibration signal. Still other prior art devices do not maintain a large file of historical and theoretical frequency information for properly functioning disc drives that can be used to compare with a test disc drive. Finally, prior art devices do not provide a user interface on which a set of useful real-time statistics and pass/fail information is displayed.
Accordingly there is a need for a method and apparatus that provides a non-invasive analysis capable of characterizing different vibrations.
SUMMARY OF THE INVENTION
Against this backdrop the present invention has been developed. One embodiment of the present invention involves an apparatus which allows for analyzing vibrations in a disc drive, without the need for opening the disc drive and applying a transducer directly to internal components, thereby avoiding the destruction of the disc drive and the waste associated therewith. Another embodiment of the present invention involves an apparatus for analyzing vibrations in a disc drive by comparing test frequency data to similar data for a reference disc drive. Another embodiment of the present invention involves locating typical frequencies and their associated magnitudes in a configuration database of reference disc drive frequency data by initially calculating theoretical frequencies based on the electromechanical characteristics of a test disc drive.
Embodiments of the invention may be implemented as a computer process, a computing system or as an article of manufacture such as a computer program product or computer readable media. The computer program product may be a computer storage media readable by a computer system and encoding a computer program of instructions for executing a computer process. The computer program product may also be a propagated signal on a carrier readable by a computing system and encoding a computer program of instructions for executing a computer process.
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Hoff Marc S.
Merchant & Gould P.C.
Raymond Edward
Seagate Technology LLC
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