Disk Device Head Position Prediction for Vibration
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Solution Overview
Problem
In disk devices, write operations are challenging due to vibrations that can cause the head to protrude from the target track, leading to shifted writing and data overwrite, with existing solutions failing to accurately predict and prevent such occurrences.
Innovation Solution
A disk device with a controller that acquires vibration source information, updates coefficients for predicting the head's position, and prohibits write operations when the predicted position exceeds a threshold, ensuring accurate write prohibition determination and preventing data shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the head moves during write operation, then write speed is improved, but positioning accuracy deteriorates due to vibration causing head protrusion from target track
Solution Approach 1:
The controller performs preliminary prediction of the head's position during write operations by acquiring vibration source information and using coefficients to estimate where the head will be. This allows the system to anticipate positioning errors due to vibration before they occur, enabling proactive adjustment or prohibition of write operations to maintain accuracy while preserving write speed capability
2Manufacturing precision
If vibration damping measures are implemented, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
Instead of implementing mechanical vibration damping measures that would increase device complexity, the patent substitutes a computational approach where the controller acquires vibration source information and uses coefficient-based calculations to predict head position. This replaces potential mechanical solutions with information processing, maintaining positioning accuracy without adding mechanical complexity to the device structure
3Manufacturing precision
If write operation is prohibited during vibration, then data accuracy is improved, but write productivity decreases
Solution Approach 1:
Rather than completely prohibiting write operations during vibration, the system applies partial action by selectively permitting writes only when the predicted head position indicates adequate accuracy. The controller evaluates vibration conditions in real-time and allows write operations when coefficients indicate the head remains within acceptable positioning tolerances, thus maintaining productivity while ensuring data accuracy when conditions permit
Data Source
AI summary
According to an embodiment, in a disk device, a first actuator moves a first head with respect to a first surface of a first disk. A controller controls positioning of the first head via the first actuator and controls a write operation to the first disk by the first head. The controller acquires information regarding a state of a vibration source, changes a value of a coefficient for estimating a predicted position of the first head according to the information regarding the state of the vibration source, estimates a predicted position of the first head with the value of the coefficient changed, performs a write operation by the first head in a case where the predicted position estimated is equal to or less than a threshold, and prohibits the write operation by the first head in a case where the predicted position estimated exceeds the threshold.