Chemical Sensor Calibration Apparatus Using Sensitivity Variation Curve Prediction
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Solution Overview
Problem
Chemical sensors, such as pH sensors, experience varying measurement sensitivity over time, leading to calibration sensitivity deviations and errors in pH measurement values, necessitating frequent calibration and complex maintenance.
Innovation Solution
A calibration apparatus that includes a conversion calculation unit, a calibration sensitivity extraction unit, a calibration history storage unit, and a sensitivity variation curve prediction unit, which predicts and continuously updates sensitivity correction values based on past calibration data to match the sensitivity variation curve to the newest calibration sensitivity, reducing deviations and the need for frequent calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed at a predetermined time interval, then measurement precision is maintained at calibration points, but sensitivity deviation increases between calibration points
Solution Approach 1:
The system performs preliminary calibration at discrete time points and then uses the sensitivity variation curve to predict and compensate for sensitivity changes continuously between calibration points. This preliminary calibration data is stored and reused to maintain measurement precision without requiring frequent recalibration.
Solution Approach 2:
The system creates a sensitivity variation curve that copies the pattern of sensitivity changes observed during calibration. This curve is then applied to correct measurements taken between calibration points, effectively copying the calibration benefits to the entire measurement period rather than just at discrete calibration moments.
2Measurement precision
If calibration frequency is increased to reduce sensitivity deviation, then measurement precision improves, but maintenance complexity and time loss increase
Solution Approach 1:
The system performs calibration preliminarily at extended intervals and stores the calibration data. The sensitivity variation curve then handles the continuous correction needs between calibrations, reducing the frequency of time-consuming calibration operations while maintaining precision.
Solution Approach 2:
Instead of repeatedly performing full calibration procedures, the system copies the sensitivity correction pattern from the variation curve to continuously correct measurements. This copying approach replaces multiple calibration operations with a single calibration plus continuous curve-based correction.
3Ease of operation
If discrete calibration sensitivity is used, then calibration process is simple, but sensitivity deviation increases over time between calibrations
Solution Approach 1:
The system transitions from static discrete calibration sensitivity values to a dynamic sensitivity variation curve that continuously adapts to sensitivity changes. The curve dynamically adjusts corrections based on the elapsed time since calibration, maintaining reliability while preserving operational simplicity.
Solution Approach 2:
The system copies the temporal pattern of sensitivity variation from the calibration period into a reusable sensitivity variation curve. This copied pattern is then applied to correct measurements between calibrations, extending the effectiveness of simple discrete calibration to continuous operation.
Data Source
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AI summary
A calibration apparatus (20) for a chemical sensor includes a conversion calculation unit (23) that acquires a measurement value of a calibration solution (22) that is measured by the chemical sensor (11) and calculates a conversion calculation output, a calibration sensitivity extraction unit (24) that receives the conversion calculation output and extracts a calibration sensitivity from the conversion calculation output, a calibration history storage unit (26) that stores past histories of the calibration sensitivity, and a sensitivity variation curve prediction unit (25) that predicts a sensitivity variation curve based on the past histories of the calibration sensitivity, the sensitivity variation curve prediction unit calculating a sensitivity correction value based on the sensitivity variation curve, the sensitivity variation curve prediction unit supplying the sensitivity correction value to a sensitivity correction part (13a) that performs a sensitivity correction in a measurement apparatus (10).