Elevator Actuator Calibration for Disk Drive Head Positioning
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Solution Overview
Problem
Conventional disk drives require multiple actuator arms and heads to access both surfaces of disks, increasing costs and complexity, while existing positioning systems face challenges in accurately calibrating actuator arms relative to position sensors, leading to variance in head positioning.
Innovation Solution
The implementation of an elevator actuator system that actuates heads along an axial dimension to access both disk surfaces with a single radial actuator, utilizing a position sensor to generate sinusoidal signals for precise head positioning, and calibrating the crashstop_offset to define a home position, thereby reducing the number of actuator arms and heads needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple actuator arms and heads are used to access both surfaces of disks, then the disk drive can access all disk surfaces, but the cost and complexity of the system increases
Solution Approach 1:
The patent merges the functionality of multiple actuator arms into a single radial actuator arm that can service both disk surfaces. The elevator actuator moves the head assembly axially between surfaces, while the single radial actuator handles radial positioning for both surfaces, eliminating the need for separate actuator arms for each surface.
Solution Approach 2:
The patent introduces axial movement as a new dimension to the traditional radial actuation system. By adding the elevator actuator that moves heads in the axial dimension between disk surfaces, the system enables single actuator arm to access multiple surfaces without requiring additional radial actuator arms for each surface.
2Measurement precision
If conventional positioning systems are used without calibration, then the system is simpler to implement, but head positioning accuracy varies due to actuator arm sensor misalignment
Solution Approach 1:
The patent implements a calibration process that is performed preliminarily during manufacturing or initialization. The calibration aligns the position sensor readings with the actual actuator arm positions by adjusting the home position offset, ensuring accurate positioning before normal operation begins.
Solution Approach 2:
The calibration process uses feedback from the position sensor to determine the actual location of the actuator arm at known positions (such as crash stop positions). This feedback information is used to calculate and apply correction offsets to the home position, thereby aligning the sensor coordinate system with the physical actuator positions.
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 reduces the cost and complexity of disk drives by minimizing the number of actuator arms and heads, while ensuring accurate and efficient head positioning across multiple disk surfaces, enhancing the overall operational efficiency.
Implementation Method 1
utilizing a position sensor to generate sinusoidal signals for precise head positioning
Implementation Method 2
a head connected to a distal end of an actuator arm which is rotated about a pivot by a voice coil motor (VCM)
Implementation Method 3
a first elevator actuator comprising a first lead screw having a first pitch actuates an actuator arm along the axial dimension
Data Source
AI summary
A data storage device is disclosed comprising a first disk comprising a first disk surface, a second disk comprising a second disk surface, an actuator arm, a head coupled to a distal end of the actuator arm, and a ramp for loading/unloading the head. A first elevator actuator is configured to actuate the actuator arm along an axial dimension relative to the first and second disks, and a second elevator actuator is configured to actuate at least part of the ramp along the axial dimension, wherein a simultaneous movement of the first and second elevator actuators is synchronized.