Disk Drive Seek Power Reduction via Adjusted Coast Velocity
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Solution Overview
Problem
Existing data storage devices, such as disk drives, face inefficiencies in seek operations due to high power consumption and potential early arrival of the head at the target track, leading to rotational latency and increased energy usage.
Innovation Solution
The solution involves adjusting the seek time by adding rotational latency, optimizing the driving current profile to minimize power consumption by deriving optimal coast velocity and coast time through specific equations, ensuring reduced power usage while avoiding resonance excitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the head seeks from track to track using conventional seek time, then the seek operation completes quickly, but power consumption increases and rotational latency occurs due to early arrival
Solution Approach 1:
The patent applies parameter changes by adjusting the seek time parameter to be longer than the conventional minimum seek time. This allows the head to arrive at the target track earlier in the rotational cycle, reducing rotational latency and power consumption. The control system modifies the driving current profile parameters (coast velocity, coast time) to achieve this optimized seek time, balancing speed and energy efficiency.
2Use of energy by moving object
If the seek time is extended to reduce power consumption, then energy efficiency improves, but productivity decreases due to longer seek operations
Solution Approach 1:
The patent applies dynamics by implementing a dynamic driving current profile that transitions between different operational phases (acceleration, coasting, deceleration) with optimized parameters. The system dynamically adjusts coast velocity and coast time to achieve the optimal balance between reduced power consumption and maintained productivity. This dynamic control allows the system to adapt the seek operation characteristics to minimize energy usage while completing operations within acceptable timeframes.
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 results in reduced seek power consumption and adjusted coast velocity, effectively utilizing rotational latency to minimize energy expenditure during seek operations in disk drives.
Implementation Method 1
a head connected to a distal end of an actuator arm which is rotated about a pivot by a voice coil motor (VCM)
Data Source
AI summary
A data storage device is disclosed comprising a disk comprising a plurality of tracks, a head, and an actuator configured to actuate the head over the disk. An adjusted seek time is determined to seek the head from a first track to a second track, and an adjusted coast velocity and an adjusted coast time of the seek is determined based on the adjusted seek time and a power consumption of the seek when a driving current applied to the actuator is substantially constant during at least one of an acceleration time and a deceleration time of the seek.