Spindle Force Actuator for Disk Run-Out Control
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Solution Overview
Problem
In magnetic recording media, the increased speed of disk rotation and simultaneous operations lead to increased noise and vibration, causing random radial displacement and eccentricity, resulting in non-repetitive run-out issues that interfere with accurate data writing and reading due to the small size and proximity of magnetic elements.
Innovation Solution
An apparatus comprising a circuit, code modulator, and actuator that detects displacements and generates a signal to apply a dampening force, specifically targeting the two dominant resonance modes contributing to non-repetitive run-out by determining the frequencies at which these modes occur and applying a force to attenuate them, thereby reducing vibrational energy and improving system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the speed at which disks rotate is increased to increase production volume, then productivity is improved, but noise and vibration increase causing non-repetitive run-out issues
Solution Approach 1:
The patent detects the harmful vibrations and non-repetitive run-out caused by high-speed rotation, then applies feedback forces through actuators to convert these harmful vibrations into beneficial controlled movements, thereby eliminating the run-out issues while maintaining high productivity
Solution Approach 2:
The patent employs a feedback mechanism where sensors detect displacements and vibrations of the rotating disk, process this information through a circuit, and generate corrective signals that drive actuators to apply counteracting forces, thereby continuously suppressing non-repetitive run-out during high-speed operation
2Productivity
If the same operations are performed on more disks simultaneously to increase production volume, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent integrates multiple functions into a single apparatus that can handle multiple disks simultaneously. The sensor board, circuit, and actuator system are designed to work with stacks of multiple disks, allowing the same equipment to process several disks in parallel without requiring separate systems for each disk
3Quantity of substance
If the size and distance between magnetic elements are reduced to increase storage capacity, then information density is improved, but measurement precision of disk position deteriorates
Solution Approach 1:
The patent applies preliminary corrective forces through the actuator system before the disk reaches positions where run-out would cause reading or writing errors. By detecting displacements in advance and applying compensating forces proactively, the system maintains accurate positioning even with densely packed magnetic elements that require high position 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
The solution effectively reduces the amplitude of non-repetitive run-out by increasing dampening force, minimizing the area defined by the dominant modes, and widening the phase change response, leading to improved performance and accuracy in disk manufacturing processes.
Implementation Method 1
applying a force to attenuate them, thereby reducing vibrational energy
Implementation Method 2
targeting the two dominant resonance modes contributing to non-repetitive run-out
Data Source
AI summary
An apparatus includes a circuit, a code modulator, and an actuator. The circuit is operable to detect displacements of a rotating object while in motion. The circuit is operable to detect a position of the displacements and to generate a signal associated therewith. The code modulator is operable to generate a modulated signal based on the position and the displacements. The actuator is operable to apply a force to the rotating object, wherein the force is based on the modulated signal.