Elevator Actuator Calibration for Disk Drive 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 the axial location of actuator arms relative to position sensors, leading to potential errors and inefficiencies.
Innovation Solution
The implementation of an elevator actuator system that actuates heads along an axial dimension to access both disk surfaces with reduced actuator arms and heads, utilizing a position sensor to generate sinusoidal signals for precise positioning, and employing crashstop_offset measurements to calibrate the home position, thereby reducing costs and improving positioning accuracy.
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 capability to access both disk surfaces is improved, but the cost and device complexity increase
Solution Approach 1:
The single actuator arm is designed to access both disk surfaces by moving the head assembly between surfaces. The head assembly can read/write from both the first and second disk surfaces using the same actuator arm, making the actuator system universal for accessing multiple surfaces rather than requiring separate actuators for each surface.
Solution Approach 2:
The patent combines the functionality of multiple actuator arms into a single actuator arm that serves both disk surfaces. The head assembly is configured to access both surfaces, merging what would traditionally require separate actuator systems into one unified mechanism, thereby reducing device complexity while maintaining full access capability.
2Measurement precision
If conventional positioning systems are used without calibration, then the system is simpler to operate, but positioning accuracy deteriorates due to errors in axial location
Solution Approach 1:
The system performs a calibration process before normal operation to establish accurate positioning. The calibration involves moving the actuator arm to a known reference position (such as a crash stop position) and adjusting the position sensor readings to match the actual physical position. This preliminary calibration action ensures high positioning accuracy during subsequent operations without requiring complex real-time adjustments.
Solution Approach 2:
The calibration process uses feedback from position sensors to detect the actual axial location of the actuator arm and compares it with the expected position. Based on this feedback, the system adjusts positioning parameters to eliminate errors, ensuring accurate head positioning relative to disk surfaces during normal operation.
3Measurement precision
If crashstop_offset calibration is performed, then positioning accuracy is improved, but the calibration time and process complexity increase
Solution Approach 1:
The calibration process is designed to be performed automatically by the system itself without requiring external intervention or complex manual procedures. The actuator arm autonomously moves to reference positions, the position sensors automatically detect the actual locations, and the system self-adjusts the calibration parameters. This self-service calibration reduces both time and operational complexity compared to manual calibration methods.
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 number of actuator arms and heads needed, lowers the cost of disk drives, and enhances positioning accuracy by accurately calibrating the axial location of actuator arms, leading to more efficient and cost-effective disk drive operations.
Implementation Method 1
utilizing a position sensor to generate sinusoidal signals for precise positioning
Data Source
AI summary
A data storage device is disclosed comprising an elevator actuator configured to actuate a head along an axial dimension, and a position sensor configured to generate a sinusoidal sensor signal representing a position of the head along the axial dimension, wherein the position sensor comprises a sensor element and an encoder strip comprising a pattern having at least one region that causes a disturbance in the sinusoidal sensor signal. The elevator actuator is controlled to move the head in a first direction along the axial dimension to detect the disturbance in the sinusoidal sensor signal, and when the disturbance in the sinusoidal signal is detected, the elevator actuator is controlled to move the head in a second direction along the axial dimension opposite the first direction in order to measure a zero crossing of the sinusoidal sensor signal.