Hard Disk Head Positioning via Inter-Plane Trajectory Error Compensation
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Solution Overview
Problem
Hard disk devices face challenges in managing inter-plane relative trajectory errors between recording heads due to factors like impact and thermal deformation, leading to increased mechanical complexity when trying to adjust head positions mechanically.
Innovation Solution
A hard disk device with a scanning mechanism that calculates and compensates for inter-plane relative trajectory errors by determining a data access order for recording heads to access bands on multiple medium surfaces, allowing data access without relying on mechanical parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical measures are taken to address inter-plane relative trajectory error by individually adjusting recording head positions, then positioning accuracy is improved, but device complexity increases significantly
Solution Approach 1:
The patent replaces mechanical adjustment mechanisms with a computational approach. The control unit calculates the inter-plane relative trajectory error based on position information from servo patterns and compensates for it through data access ordering, eliminating the need for mechanical position adjustment mechanisms while maintaining positioning accuracy.
Solution Approach 2:
The patent changes the parameter being controlled from physical head position to logical data access order. Instead of mechanically adjusting head positions to compensate for trajectory errors, the system maintains fixed head positions and compensates by reordering data access sequences based on calculated error values.
2Reliability
If the number of components is increased to compensate for trajectory errors, then reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent replaces additional mechanical components with software-based compensation. The control unit uses algorithms to calculate and compensate for trajectory errors, achieving reliable operation without increasing the number of physical components, thereby maintaining ease of manufacture.
Solution Approach 2:
The system performs self-compensation for trajectory errors using its own computational resources. The control unit automatically calculates errors based on servo pattern readings and adjusts data access ordering without requiring external calibration or additional adjustment mechanisms.
Data Source
AI summary
A hard disk device comprises a scanning mechanism that simultaneously scans a first recording medium surface with a first recording head and a second recording medium surface with a second recording head, a table storing band relative position information for a first band on the first recording medium surface and a second band on the second recording medium surface, and a processor. The processor calculates an inter-plane relative trajectory error between the first and second recording heads, determines a data access order performed by the first recording head on the first band and the second recording head on the second band, based on the band relative position information and the inter-plane relative trajectory error, and causes the first recording head to access a track and the second recording head to access a track in the data access order determined by the determining unit.