Transducer Head Fly Height Calibration Using Adaptive Wavelet Transform
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Solution Overview
Problem
Disc drive systems require extensive calibration to set the optimal fly height of the transducer head, which can result in damage due to prolonged contact with the media during the calibration process, and existing methods are time-consuming and inefficient.
Innovation Solution
The implementation of an adaptive discrete wavelet transform (ADWT) method using data samples from a proximity sensor to determine the active fly height setting, allowing for faster calibration by reducing contact time between the transducer head and the disc through thermal expansion control and efficient data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If extensive calibration is performed to set the optimal fly height, then manufacturing precision is improved, but productivity deteriorates due to prolonged contact time between transducer head and media
Solution Approach 1:
The patent applies preliminary action by performing a rough calibration to establish an initial close point setting before the final precision calibration. This preliminary step positions the transducer head close to the media surface, allowing the subsequent precision calibration to be completed within less than one revolution, thus resolving the contradiction between precision and speed
Solution Approach 2:
The patent implements the skipping principle by rushing through the final calibration step once the close point is established. The system quickly determines the active fly height setting by analyzing data collected during less than one revolution, avoiding prolonged contact while maintaining precision
2Manufacturing precision
If extensive calibration is performed to set the optimal fly height, then manufacturing precision is improved, but loss of time increases due to prolonged calibration duration
Solution Approach 1:
The patent uses preliminary action by establishing the close point setting first, which prepares the system for rapid final calibration. This preliminary positioning enables the precision calibration to be completed in less than one revolution, significantly reducing calibration time while maintaining precision
Solution Approach 2:
The patent applies partial action by collecting data only during the critical portion of the rotation (less than one revolution) after the close point is established. This partial data collection is sufficient for determining the active fly height setting, avoiding unnecessary time loss from complete revolution calibration
3Manufacturing precision
If prolonged contact between transducer head and media occurs during calibration, then manufacturing precision is improved, but object-affected harmful factors increase due to damage risk
Solution Approach 1:
The patent applies preliminary action by establishing the close point setting before final calibration, which positions the transducer head optimally close to the media. This preliminary step minimizes the contact time required for precision calibration, thereby reducing damage risk while maintaining precision
Solution Approach 2:
The patent implements skipping by rapidly completing the final calibration step once the close point is established, determining the active fly height setting within less than one revolution. This rapid completion minimizes prolonged contact and associated damage risks
4Measurement precision
If traditional calibration methods are used, then measurement precision is achieved, but device complexity increases due to extended calibration procedures
Solution Approach 1:
The patent uses preliminary action by establishing the close point setting before final calibration, which simplifies the subsequent precision measurement step. This preliminary positioning allows accurate measurement to be completed rapidly, reducing overall process complexity while maintaining measurement precision
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 enables rapid calibration within less than a single disc revolution, reducing damage risk and improving bit-error-rate performance, while allowing for dynamic adjustments and increased manufacturing output.
Implementation Method 1
a thermal expansion device to move a close point of the transducer head closer to the disc surface
Data Source
AI summary
In one implementation, a method and apparatus is provided for determining an active fly height setting for a transducer head from samples collected from a proximity sensor during less than a single revolution of a disc. Implementations of the method and system use adaptive discrete wavelet transform parameters generated from the collected samples to determine an active fly height setting for a transducer head.