Magnetic Disk Head Speed Control for Spiral Pattern Alignment
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Solution Overview
Problem
The instability of gaps between spiral reference patterns written on a magnetic disk due to external forces can cause them to cross, preventing the execution of the servo pattern writing process in magnetic disk devices.
Innovation Solution
A magnetic disk device with a controller that includes control sections to write, track, detect shifts, and correct the movement speed of a magnetic head to maintain predetermined gaps between reference patterns, ensuring proper alignment and preventing pattern crossing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the magnetic head moves at a constant regulated speed to write spiral reference patterns, then the writing process is simple and efficient, but external forces cause the gaps between patterns to become unstable and patterns may cross
Solution Approach 1:
The system detects the actual position of the magnetic head relative to the written spiral pattern and uses this feedback to correct the head movement speed. The detection section measures the shift between the head locus and the reference pattern, and the correction section adjusts the regulated speed based on this detected shift to maintain stable gaps between patterns.
Solution Approach 2:
The patent replaces pure mechanical constant-speed movement with a controlled speed adjustment system. Instead of relying solely on mechanical precision to maintain constant gaps, the system uses detection and correction mechanisms to dynamically adjust the head movement speed, substituting mechanical rigidity with active control.
2Manufacturing precision
If the magnetic head movement speed is adjusted to correct pattern alignment, then gap stability improves, but the control system becomes more complex
Solution Approach 1:
The correction section implements feedback control by detecting the shift between the magnetic head locus and the reference pattern, then adjusting the regulated speed accordingly. This closed-loop feedback mechanism automatically corrects alignment issues without requiring complex manual intervention or overly sophisticated control systems.
Solution Approach 2:
The system performs self-correction by using the detected pattern shift information to automatically adjust its own head movement speed. The correction section modifies the regulated speed based on the detected alignment status, enabling the system to self-regulate and maintain pattern stability without external intervention.
3Reliability
If external forces act on the actuator or flexible circuit board, then the magnetic head position becomes unstable, but these external forces cannot be eliminated
Solution Approach 1:
The detection section continuously monitors the actual position of the magnetic head and detects shifts caused by external forces. This feedback information is fed to the correction section, which adjusts the regulated speed to compensate for the disturbance, thereby maintaining head position stability despite external force influences.
Solution Approach 2:
The system converts the harmful effect of external forces into useful information. By detecting the position shifts caused by external forces, the system uses this information to adjust the head movement speed in a way that compensates for the disturbance, turning the adverse effect into an opportunity for correction and improved stability.
Data Source
AI summary
A magnetic disk device detects a shift of writing positions of a spiral pattern, corrects the regulation speed in a direction where the shift is canceled, and writes spiral patterns based on the corrected regulation speed.