Disk Storage Head Retraction Control for Power Saving
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Solution Overview
Problem
Current magnetic disk devices face challenges in reducing power consumption during the head retraction operation, which is essential for protecting data during power shutdown, as existing techniques do not adequately address energy saving and stability in this process.
Innovation Solution
A control device with a control unit, acquisition unit, and calculation unit that determines the moving distance of the head to accurately switch from a first retract operation to a second retract operation, reducing power consumption by using the head's moving distance instead of back electromotive force for determination, thereby optimizing the retraction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the head is retracted to the ramp mechanism during power shutdown, then data protection is achieved, but power consumption increases
Solution Approach 1:
The retraction operation is divided into multiple phases: a first retract operation that moves the head toward the ramp mechanism, and a second retract operation that completes the retraction. This segmentation allows the system to optimize power consumption by switching between different operational modes at appropriate points in the retraction process.
Solution Approach 2:
The control unit dynamically switches between the first and second retract operations based on the head's position and movement characteristics. By adaptively adjusting the retraction strategy in real-time, the system achieves reliable data protection while minimizing power consumption during the shutdown process.
2Use of energy by moving object
If the retraction operation is optimized for energy saving, then power consumption is reduced, but the stability of data protection may be compromised
Solution Approach 1:
The control unit monitors the head's position and retraction progress, using this feedback information to determine when to switch between the first and second retract operations. This feedback mechanism ensures that the head is reliably retracted to the ramp mechanism while optimizing power consumption based on actual operational conditions.
Solution Approach 2:
The system changes operational parameters (switching between different retract operations) based on the retraction progress and system state. By adjusting these parameters dynamically, the system maintains stable data protection while achieving energy optimization during the power shutdown process.
3Use of energy by moving object
If the head position determination is inaccurate, then power consumption cannot be optimized, but the retraction operation may fail to protect data
Solution Approach 1:
The system performs preliminary retraction movement (first retract operation) before committing to the final retraction position. This preliminary action allows the system to assess the situation and make informed decisions about completing the retraction, ensuring both accurate position determination and power consumption optimization.
Solution Approach 2:
The retraction process is made dynamic with the ability to switch between different operational modes based on real-time position determination. This dynamic approach allows the system to continuously improve measurement accuracy while optimizing power consumption throughout the retraction sequence.
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 during the retraction operation, ensuring more stable data protection by accurately determining the head's position and adjusting the voltage and time accordingly, thus enhancing the reliability of data protection.
Implementation Method 1
an operation to detect a back electromotive voltage (BEMF) generated in the VCM
Data Source
AI summary
A control device is provided which can perform a retraction operation of a head included in a disk storage device with lower power consumption.The control device of the disk storage device includes a control unit that controls a motor and retracts the head from over a disk to a ramp mechanism when power supply is shut down, an acquisition unit that acquires information related to a moving distance of the head that retracts to the ramp mechanism, and a calculation unit that calculates the moving distance of the head based on the information acquired by the acquisition unit. The control unit switches an operation of the motor from a first retract operation to a second retract operation when determining that the head reaches a first position after passing through an inclined surface of the ramp mechanism based on the moving distance calculated by the calculation unit.