Split Actuator Control for Vibration Attenuation in Data Storage
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Solution Overview
Problem
Current data storage devices face challenges in accurately positioning heads over disk surfaces due to vibrations and disturbances, which affect the precision of read/write operations and lead to position error signals that are not effectively mitigated by existing servo control systems.
Innovation Solution
The implementation of a split actuator configuration with independent control of inner and outer fine actuators, where the fine actuators for top and bottom disk surfaces are mechanically equivalent but flipped in orientation, allowing for concurrent actuation in opposite radial directions to attenuate vibration modes, and the use of control circuitry to generate and apply control signals effectively to these actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single fine actuator is used for head positioning, then the device complexity is reduced, but the head positioning precision deteriorates due to vibrations and disturbances
Solution Approach 1:
The actuator system is divided into two independent fine actuators (first fine actuator and second fine actuator) that can be controlled separately. This segmentation allows each actuator to handle specific vibration attenuation tasks, improving head positioning precision by counteracting disturbances that would affect a single actuator system.
2Measurement precision
If inner and outer fine actuators are controlled independently, then the positioning accuracy is improved by attenuating vibration modes, but the control system complexity increases
Solution Approach 1:
The control system dynamically adjusts the operation of inner and outer fine actuators based on real-time vibration conditions. During seek operations, both actuators are activated to attenuate vibrations. During constant linear velocity operations, only the outer fine actuator operates. This dynamic control strategy improves positioning accuracy while managing control system complexity through adaptive operation modes.
3Object-affected harmful factors
If fine actuators operate in opposite radial directions, then vibration attenuation is enhanced, but the mechanical design complexity increases
Solution Approach 1:
The first and second fine actuators are positioned asymmetrically at different radial locations (inner and outer regions) of the actuator arm. This asymmetric configuration allows them to operate in opposite radial directions to attenuate different vibration modes. The mechanical design incorporates this asymmetry to achieve enhanced vibration attenuation while managing structural complexity.
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 configuration enhances the precision of head positioning by effectively attenuating vibrations and disturbances, improving the accuracy of read/write operations and reducing position error signals, thereby enhancing the overall performance of data storage devices.
Implementation Method 1
fine actuators configured to actuate the heads radially over the top and bottom disk surfaces
Implementation Method 2
allowing for concurrent actuation in opposite radial directions to attenuate vibration modes
Data Source
AI summary
Control circuitry is disclosed configured to control inner fine actuators of a first plurality of inner actuator arms and independently control a first outer fine actuator of a first outer actuator arm. Inner fine actuators of a second plurality of inner actuator arms are controlled while independently controlling a second outer fine actuator of a second outer actuator arm. Each actuator arm comprises at least one head configured to access a disk surface of a disk.