Disk Storage Virtual Circular Orbit Position Error Reduction
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Solution Overview
Problem
Conventional disk storage devices using virtual circular control experience errors in decoded position due to relative velocity between the head and the disk, as they disregard the disk's eccentricity, leading to diagonal traversal of servo patterns and positional inaccuracies.
Innovation Solution
The implementation of a disk storage device with a controller that generates a second timing signal for reading position signals along a virtual circular orbit, where the period is shorter than the first timing signal, and the center time is shifted closer to the demodulation center, reducing errors by aligning the magnetic head on a virtual circular orbit independent of the disk's eccentricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If virtual circular control is performed by disregarding disk eccentricity, then the head can be controlled on a circular orbit independent of disk eccentricity, but a relative velocity occurs between the head and the disk causing error in the decoded position
Solution Approach 1:
The patent changes the timing parameters for reading position signals by generating a second timing signal with a shorter period and shifted center time compared to the first timing signal. This parameter adjustment compensates for the relative velocity effect between the head and disk during virtual circular control, thereby reducing decoded position errors while maintaining position detection accuracy
Solution Approach 2:
The patent uses feedback from the detected position signals to adjust the timing of subsequent readings. By continuously monitoring the position and adjusting the timing signal based on the relative velocity between head and disk, the system compensates for positioning errors in real-time during virtual circular control operations
2Measurement precision
If the timing period for reading position signals is shortened and center time is shifted, then the position error is reduced, but the complexity of the control system increases
Solution Approach 1:
The patent pre-calculates and stores the optimal timing parameters (shorter period and shifted center time) in advance based on the virtual circular control requirements. By preparing the corrected timing signal parameters beforehand rather than calculating them in real-time, the system reduces position errors while minimizing the increase in control system complexity
Solution Approach 2:
The patent introduces a timing signal generator as an intermediary component that converts the standard timing signal into a corrected timing signal with adjusted period and center time. This intermediary element handles the complexity of timing adjustments separately, allowing the main control system to remain relatively simple while still achieving improved position accuracy
Data Source
AI summary
According to one embodiment, a disk storage device includes: a disk on which a servo pattern is recorded; a head; a driver; a signal generator; a demodulator; and a controller. Position signals for detecting an offset position from a center of a track are recorded in a recording area of a servo pattern. The signal generator generates a first timing signal indicating a timing for reading the position signals. When the controller performs positional control along a virtual circular orbit of the disk, the signal generator generates a second timing signal. The period of the second timing signal for reading each of the position signals is made shorter than that of the first timing signal. A center time of the period of the second timing signal is shifted closer to a demodulation center time corresponding to a center of the recording area than that of the first timing signal.