Disk Device Motor Current Waveform Optimization
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Solution Overview
Problem
Existing disk devices face challenges in reducing power consumption while maintaining effective control operations, particularly during seek operations on disk devices equipped with motors.
Innovation Solution
The disk device employs a controller that manages the motor current by increasing its absolute value during acceleration or deceleration, changing it at specific average change rates in different sections of the seek period, and adjusting these rates based on the presence or absence of a rotation waiting time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If motor current is increased during seek operations to improve access performance, then seek speed is improved, but power consumption increases
Solution Approach 1:
The seek period is divided into multiple sections (first section, second section, third section, fourth section, fifth section) with different current control strategies. The controller segments the current waveform into distinct phases: initial current increase phase, first constant current phase, current decrease phase, second current increase phase, and final constant current phase. This segmentation allows optimization of power consumption in each phase while maintaining overall seek performance.
Solution Approach 2:
The motor current is dynamically adjusted based on the seek phase and rotation waiting time conditions. The controller changes current magnitude and timing adaptively: when rotation waiting time is present, current is increased in the fourth section; when absent, current is increased in the first section. This dynamic current control optimizes the balance between seek speed and power consumption based on real-time operational conditions.
2Use of energy by moving object
If motor current waveform is optimized to reduce power consumption, then energy efficiency is improved, but access performance may deteriorate
Solution Approach 1:
The controller uses feedback from rotation waiting time detection to adjust current waveform characteristics. By monitoring whether rotation waiting time is present, the controller selects appropriate current control patterns that maintain access performance while reducing power consumption. The feedback mechanism ensures that current is applied at optimal moments to maintain seek reliability.
Solution Approach 2:
The controller changes current parameters (magnitude, timing, duration) based on operational conditions. Current absolute value is increased in specific sections (first or fourth section) depending on rotation waiting time presence. This parameter adjustment allows the system to maintain adequate seek performance while minimizing power consumption through optimized current waveforms.
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 reduces power consumption by optimizing the motor current waveform, achieving lower power consumption without compromising access performance, especially during seek operations.
Implementation Method 1
a voice coil motor (VCM) 13 that moves the arm 2 in a radial direction of the disk 1 by applying a current to a coil
Data Source
AI summary
According to one embodiment, in a disk device, a controller, when the rotation waiting time is present, increases an absolute value of a motor current in a fourth section in a second period in which a head is accelerated or decelerated, changes the absolute value of the motor current at a third average change rate in a fifth section after the fourth section in the second period, decreases the absolute value of the motor current at a fourth average change rate steeper than the third average change rate in a sixth section after the fifth section in the second period, and decreases the absolute value of the motor current at a fifth average change rate steeper than the fourth average change rate in a seventh section after the sixth section in the second period.