Accelerometer Resonance Detection via Bias Voltage Impulse
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Solution Overview
Problem
Existing methods for determining the mechanical resonance of accelerometers in hard disk drives are inefficient, relying on mechanical hammer shocks and spectrum analyzers, which are not practical for continuous monitoring and compensation during normal operation.
Innovation Solution
A system and method that applies a bias voltage impulse signal to the accelerometer to detect zero crossing cycles of the sensor output signal, allowing for the determination of resonance frequency and programming of filters to filter out this resonance, enabling effective monitoring of shock and vibration in both test and normal modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical hammer shock is applied to the accelerometer to determine resonance frequency, then the resonance frequency can be measured using a spectrum analyzer, but the process is not practical for continuous monitoring and requires manual intervention during manufacturing
Solution Approach 1:
The patent replaces the mechanical hammer shock method with an electrical impulse signal applied through the bias voltage terminal. This electrical excitation method eliminates the need for mechanical contact and manual spectrum analysis, enabling automated and continuous resonance frequency measurement during normal operation without requiring separate manufacturing steps
Solution Approach 2:
The accelerometer system performs self-diagnosis by using its own output signal to determine its resonance frequency. The controller analyzes the accelerometer's response to the electrical impulse and automatically identifies the resonance frequency, eliminating the need for external spectrum analyzers and manual measurement processes
2Measurement precision
If a mechanical hammer shock method is used to determine resonance frequency, then the resonance can be measured, but the process is time-consuming and not suitable for automated manufacturing
Solution Approach 1:
The patent replaces time-consuming mechanical hammer shocks with rapid electrical impulse signals that can be applied and analyzed automatically by the controller. This enables resonance frequency determination to be performed quickly during normal operation without requiring separate manufacturing steps or manual spectrum analysis
Solution Approach 2:
The resonance frequency determination is performed as a preliminary action during normal operation before any shock or vibration monitoring begins. The controller automatically measures the resonance frequency and programs the filter accordingly, so that when actual shock events occur, the system is already configured for optimal performance
3Device complexity
If the accelerometer operates without resonance filtering, then the system remains simple, but shock and vibration disturbances can cause off-track writes and data loss
Solution Approach 1:
The system performs preliminary action by automatically determining the resonance frequency and programming the appropriate filter parameters before any actual shock or vibration events occur. This ensures that the filtering system is pre-configured and ready to protect against resonance-induced head positioning errors without adding complexity to the operational mode
Solution Approach 2:
The controller uses feedback from the accelerometer's response to the electrical impulse signal to automatically determine the resonance frequency and adjust the filter parameters. This closed-loop approach ensures that the filtering system adapts to the specific characteristics of each accelerometer, improving reliability while maintaining simplicity through automation
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
Enables accurate and efficient determination of mechanical resonance, allowing for robust compensation of shock and vibration in hard disk drives, preventing data loss by filtering out resonance frequencies and aborting write operations when thresholds are exceeded.
Implementation Method 1
The accelerometer has mechanical force sensing elements with a mechanical resonance. To sense the shock or vibration correctly during normal operation, the resonance frequency of the accelerometer needs to be determined
Implementation Method 2
The accelerometers generate a signal which can be used as a feed forward controller to make the disk drive more robust to shocks and vibrations
Implementation Method 3
a zero crossing detector configured to detect zero crossing cycles of a sensor output signal response to the bias voltage impulse signal
Implementation Method 4
The accelerometer response should include the mechanical resonance of the accelerometer, which can be measured by a spectrum analyzer and employed to program the low pass filter or notch filter during manufacturing
Data Source
AI summary
Systems and methods are provided for determining mechanical resonance of a sensor. In one embodiment, a system is provided that comprises a bias voltage source configured to apply a bias voltage impulse signal to a terminal of the sensor and a zero crossing detector configured to detect zero crossing cycles of a sensor output signal response to the bias voltage impulse signal. The system further comprises a controller configured to determine the resonance frequency of the sensor based on the detected zero crossing cycles of the sensor output signal response.