Magnetic Disk Drive Microactuator Voltage Control for Multi-Head Positioning

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Solution Overview

Problem

In multi-stage microactuator-type magnetic disk drives, applying large absolute voltages to microactuators can lead to degradation of elements, especially when multiple heads are simultaneously positioned on different disk surfaces for read and write operations.

Innovation Solution

The magnetic disk drive controls the input voltage to each microactuator to prevent degradation by considering the maximum voltage that can be input, allowing simultaneous read and write operations across multiple heads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If large absolute voltage is applied to microactuators to enable simultaneous read and write operations across multiple heads, then productivity is improved, but reliability deteriorates due to element degradation

Engineering Contradiction:

Improvesimultaneous read and write operationsVSAvoidmicroactuator element degradation

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent dynamically adjusts the voltage parameter applied to microactuators based on their current state and operational requirements. By changing voltage levels adaptively rather than applying constant high voltage, the system achieves high productivity when needed while preventing element degradation through lower voltages during normal operation or when simultaneous operations are not required.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system transitions from static voltage application to dynamic voltage control, where the voltage applied to microactuators is adjusted in real-time based on operational conditions. This allows the system to optimize between productivity and reliability by applying high voltage only when simultaneous read/write operations are actually needed, and using lower voltages otherwise to prevent degradation.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If independent voltage control is implemented for all microactuators on all heads, then adaptability is improved, but device complexity increases

Engineering Contradiction:

Improveindependent voltage controlVSAvoidcontrol system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control system is segmented into hierarchical levels: a central controller that manages overall coordination and individual microactuator controllers that handle local voltage regulation. This segmentation allows independent voltage control for adaptability while distributing control logic to reduce central complexity and enable modular implementation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a universal control architecture where the same control mechanism and voltage regulation logic can be applied to all microactuators across multiple heads. This multi-functional approach allows the system to handle different operational scenarios (simultaneous read/write, sequential operations, positioning) using a unified control framework, reducing overall system complexity despite the need for independent control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This approach effectively prevents the degradation of microactuator elements while enabling simultaneous read and write operations across multiple heads in the magnetic disk drive.

Implementation Method 1

a voice coil motor (VCM) that moves the plurality of heads to a predetermined position on the disk

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

a plurality of microactuators, one or more of the microactuators being included in each of the plurality of heads and all of the microactuators being capable of driving independently

Methodology Applied

Scientific EffectElectromechanical actuation: Electromechanical Film

Data Source

PatentUS20250292794A1Magnetic disk drive

Publication Date: 2025.09.18 KK TOSHIBA

AI summary

According to one embodiment, a magnetic disk drive includes rotatable disks, heads, microactuators, a voice coil motor (VCM), and a control system, wherein the control system determines a final set of heads of target for simultaneously positioned on their respective target tracks from among the heads, by using at least a displacement amount of the microactuators, determines a target position of the VCM when the heads in the final set are simultaneously positioned on their respective target tracks, switches a controller of the VCM when the heads in the final set are simultaneously positioned on their respective target tracks, and switches controller of the microactuators included in each of the heads in the final set.