Disk Drive Contact Detection Using Zone Representative Values
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Solution Overview
Problem
Existing methods for detecting the contact point between a head member and a ramp member in disk drives suffer from low accuracy due to variations in measured values, susceptibility to disturbing forces, and non-monotonic trends in force changes, leading to incorrect identification of the contact point.
Innovation Solution
A contact-detecting method that divides the disk into radial zones with multiple measuring points, calculates a representative value for each zone, and detects the contact point based on the difference between the current measured value and the representative value of the previous zone, allowing for an unfixed origin of measurement and effective detection regardless of monotonic trends or steep/gradual force changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single measuring point is used to detect contact point, then the measurement process is simple, but the detection accuracy is low due to measurement variations and disturbing forces
Solution Approach 1:
The patent divides the disk into multiple radial zones, each containing multiple measuring points. Instead of using a single measuring point, the system measures force values at multiple points within each zone and calculates a representative value (such as average or median) for that zone. This segmentation approach reduces the impact of local measurement variations and disturbing forces, thereby improving contact point detection accuracy while maintaining a manageable measurement system complexity through systematic data processing.
2Reliability
If force measurement is performed continuously, then the contact point can be detected, but the measurement is susceptible to non-monotonic trends and disturbing forces
Solution Approach 1:
The patent combines multiple force measurements taken at different measuring points within the same radial zone to generate a single representative value for that zone. By merging these measurements through statistical processing (such as averaging or taking the median), the system eliminates the effects of non-monotonic trends and disturbing forces that would affect individual measurements, thereby improving the reliability of contact point detection.
Solution Approach 2:
The system uses the representative values from multiple zones as feedback to identify the contact point. By comparing the representative values across different radial zones and detecting where the force application pattern changes, the system can reliably determine the contact point position despite the presence of disturbing forces during the measurement process.
Data Source
AI summary
According to one embodiment, a contact-detecting method includes calculating a representative value for each of a plurality of first zones. The plurality of first zones is provided at different radial locations on the disk. The representative value is calculated based on values measured at a plurality of different radial locations included in each of the first zones. The method includes detecting a contact point at which a first member contacts with a second member based on a first difference. The first difference is a difference between a value measured at an objective measuring point and a representative value of a second zone among the plurality of first zones. The objective measuring point is included in a third zone among the plurality of first zones. The second zone is arranged radially inward of the third zone.