Z-Axis Non-Operation Shock Detection Using Higher Harmonics
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Solution Overview
Problem
Current methods for detecting non-operation shock (NOS) in disc drives, particularly Z-axis NOS, are inadequate, leading to misclassification and non-detection, resulting in unnecessary recalibration and potential data integrity issues.
Innovation Solution
The detection of NOS is based on changes in the vector of harmonics other than the first harmonic, such as the second, third, or twelfth harmonic of the spindle, allowing for more accurate determination of NOS occurrence and reducing misclassification and non-detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current methods for detecting non-operation shock (NOS) in disc drives are used, then the detection process is simple, but the accuracy of NOS detection is poor leading to misclassification and non-detection
Solution Approach 1:
The patent changes the detection parameter from first harmonic vector to higher-order harmonic vectors (second, third, or twelfth harmonics). This parameter change enables more accurate detection of Z-axis NOS events because higher-order harmonics are more sensitive to the specific mechanical disturbances caused by axial shocks, thereby resolving the contradiction between detection accuracy and method complexity.
Solution Approach 2:
The patent transitions from using a single harmonic dimension (first harmonic) to multiple harmonic dimensions (second, third, or twelfth harmonics). This dimensional expansion in the frequency domain provides additional information about the shock event, improving detection accuracy while maintaining manageable system complexity through selective harmonic analysis.
2Productivity
If current NOS detection methods are used, then the detection system is simple, but unnecessary recalibration occurs due to misclassification
Solution Approach 1:
The patent implements a feedback mechanism where the NOS detector continuously monitors higher-order harmonic vectors and compares them against threshold values. When a genuine NOS event is detected through this feedback loop, appropriate recalibration is triggered; when normal variations occur, no recalibration is performed. This eliminates unnecessary recalibration events and associated productivity losses while maintaining drive performance.
3Reliability
If current NOS detection methods are used, then the detection process is quick, but data integrity issues arise due to non-detection of actual NOS events
Solution Approach 1:
The patent exploits the mechanical vibration characteristics of the disc drive spindle system by analyzing higher-order harmonic vectors that are generated during NOS events. These harmonic vibrations are distinct signatures of axial shocks that affect data integrity. By monitoring these specific vibration patterns, the system can reliably detect actual NOS events that would otherwise go unnoticed, thereby protecting data integrity without excessive complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the accuracy of NOS detection, reducing unnecessary recalibration and ensuring better drive performance by effectively identifying NOS-induced changes in the disc drive.
Implementation Method 1
determine an occurrence of NOS based at least in part on a change in vector of at least one harmonic of the spindle other than a first harmonic
Data Source
AI summary
Systems and methods for determining an occurrence of non-operation shock (NOS) in a disc drive are described. Such determining may be used to determine whether or not the disc drive should be recalibrated or compensated to account for changes induced by NOS. Determining NOS may be based at least in part on a harmonic of the spindle of the disc drive other than the first harmonic, such as a third harmonic of the spindle. In some embodiments, determining NOS may be based on the first harmonic of the spindle and at least one other harmonic of the spindle.