Temperature-Adaptive High-Pass Filtering for Consistent SPM Alerts
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Solution Overview
Problem
Current statistical process monitoring (SPM) systems face challenges in setting common alert thresholds for sensors operating at different temperatures and ranges due to variations in standard deviation frequency responses, which are affected by temperature, sensor range, and manufacturing variability, leading to inconsistent and unreliable alerts.
Innovation Solution
A dynamic high pass filter is constructed that normalizes the standard deviation frequency response by adjusting filter parameters based on temperature, removing variations caused by temperature changes, sensor range, and manufacturing differences, allowing for consistent alert thresholds across different operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed filter is used for statistical process monitoring, then the system is simple to implement, but the standard deviation frequency response varies with temperature and sensor range leading to inconsistent alerts
Solution Approach 1:
The patent implements a dynamic filter construction approach where filter parameters are adjusted based on temperature and sensor range measurements. The system transitions from a fixed filter to a dynamic filter that adapts its characteristics to match the current operating conditions, ensuring consistent standard deviation frequency response across varying temperatures and sensor ranges.
Solution Approach 2:
The system changes filter parameters (such as cutoff frequency and filter order) based on measured temperature and sensor range values. By dynamically adjusting these parameters, the filter maintains optimal performance and produces consistent statistical process monitoring alerts regardless of operating conditions.
2Reliability
If temperature-dependent filter parameters are used, then alert consistency across different temperatures is improved, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical or manual filter adjustment mechanisms with an electronic/digital system that automatically adjusts filter parameters based on temperature sensors and microcontroller logic. This substitution maintains alert consistency while reducing the need for manual intervention and complex physical adjustment mechanisms.
Solution Approach 2:
The system performs self-adjustment of filter parameters based on its own temperature measurements and sensor range detections. The microcontroller automatically selects appropriate filter characteristics without requiring external calibration or manual intervention, making the system self-sufficient in maintaining optimal performance across varying conditions.
3Measurement precision
If separate alert thresholds are set for each sensor and temperature condition, then measurement precision is maintained, but the ease of operation decreases
Solution Approach 1:
The patent creates a universal filter construction method that works across all sensors and temperature conditions through dynamic parameter adjustment. Instead of requiring separate configurations for each sensor-temperature combination, the system uses a single unified approach that adapts to different conditions, making the system easier to operate while maintaining measurement precision.
Solution Approach 2:
The system segments the operating conditions into discrete temperature ranges and sensor range categories, with pre-determined filter parameters for each segment. This segmentation allows the complex multi-condition problem to be broken down into manageable discrete states, simplifying both the configuration and operation while maintaining precision across all conditions.
Data Source
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AI summary
A sensing system includes a filter construction module (930) that constructs a high pass filter (902) for filtering sensor values indicative of a process variable. The filter construction module (930) setting values for parameters of the filter based on a temperature value indicative of a temperature of the sensor (246) that produced the sensor values.