Sensor Signal Filtering for Shock and Thermal Pop Detection
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Solution Overview
Problem
Data storage devices, such as disk drives, face challenges in accurately detecting and distinguishing between different types of disturbances like shock and thermal popping, which affect the head positioning and data access operations, leading to potential write aborts and reduced system reliability.
Innovation Solution
The implementation of a sensor system with multiple filters configured to detect and filter sensor signals at specific frequency ranges corresponding to shock, thermal popping, and acceleration events, allowing for the generation of distinct signals that improve disturbance detection and compensation, thereby enhancing the signal-to-noise ratio and reducing write aborts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single sensor system is used to detect all disturbances, then device complexity is reduced, but measurement precision deteriorates because shock and thermal popping signals cannot be accurately distinguished
Solution Approach 1:
The sensor system is segmented into multiple independent filters, each tuned to detect specific disturbance types (shock, thermal popping, acceleration). This segmentation allows each filter to specialize in detecting particular frequency ranges, improving measurement precision for distinguishing between different disturbance types while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
Each filter in the system is assigned specific local quality characteristics - different frequency response curves and detection thresholds optimized for particular disturbance types. The shock filter responds to high-frequency impulses, the thermal popping filter to low-frequency drifts, and the acceleration filter to gravitational changes, allowing precise local detection capabilities across the system.
2Measurement precision
If multiple filters are used to distinguish disturbance types, then measurement precision improves, but device complexity increases
Solution Approach 1:
The control circuitry is designed with multi-functionality, serving both as the processing unit for the sensor signals and as the disturbance response controller. This universal design reduces overall device complexity by consolidating functions that could otherwise require separate dedicated circuits, while still maintaining the precision benefits of multiple specialized filters.
Solution Approach 2:
Multiple filter functions are merged into a single integrated control circuitry unit that processes all sensor signals. Rather than having separate physical filter modules for shock, thermal popping, and acceleration detection, the system combines these filtering functions within one control unit, reducing device complexity while preserving measurement precision through software or integrated circuit implementation.
3Reliability
If disturbance detection is improved through filtering, then reliability improves, but loss of time increases due to additional signal processing
Solution Approach 1:
The filter system performs preliminary action by continuously monitoring and pre-processing sensor signals in real-time, maintaining ready-to-use disturbance detection capabilities. This allows the system to quickly respond to actual disturbances without requiring additional processing time when events occur, as the filtering and initial analysis are continuously performed in the background.
Solution Approach 2:
The filter design allows rapid signal processing by using optimized filter algorithms that can quickly analyze sensor inputs and identify disturbance patterns. The system rushes through the signal processing pipeline efficiently, using threshold-based detection and frequency-domain filtering techniques that minimize computational overhead while maintaining high reliability in disturbance detection.
Data Source
AI summary
A data storage device is disclosed comprising a head actuated over a disk, and a sensor configured to generate a sensor signal representing at least one of a shock and a thermal popping affecting the data storage device. The sensor signal is first filtered based on a first frequency range corresponding to the shock to generate a shock signal, and second filtered based on a second frequency range corresponding to the thermal popping to generate a pop signal, wherein the second frequency range is different from the first frequency range. The shock signal and the pop signal are individually processed, for example, to log a disturbance event, to abort a write operation, or to generate a feed-forward servo compensation signal.