Sensor Calibration Using Temperature Sensitivity for Humidity Compensation
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Solution Overview
Problem
Existing sensor calibration methods fail to account for influences from environmental factors like humidity, leading to systematic errors in sensor readings, especially after sensors are exposed to changing conditions post-production.
Innovation Solution
A method for calibrating sensors by recording sensor characteristics at different temperatures, determining the influence of environmental factors through functional relations, and compensating for these influences using linear transformations based on temperature sensitivity, ensuring accurate readings by averaging sensor data from both dry and humid states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If calibration is performed in a dry state directly after production, then calibration time is reduced and production efficiency is improved, but systematic errors occur after sensors absorb humidity leading to wrong readings
Solution Approach 1:
The patent applies preliminary action by performing calibration in the dry state directly after production before humidity absorption occurs. The calibration data collected in this initial state serves as a baseline, and subsequent drift caused by humidity absorption is compensated by comparing against this pre-established reference, thus maintaining both fast calibration and accurate readings.
Solution Approach 2:
The patent utilizes parameter changes by monitoring how sensor output drifts as humidity levels change over time. By tracking these parameter changes (output signal variations) in response to humidity absorption, the system can calculate compensation values that correct the initial calibration data, maintaining accuracy without requiring re-calibration in humid conditions.
2Measurement precision
If calibration is performed after humidity absorption, then reading accuracy is improved, but calibration time increases significantly due to slow saturation process
Solution Approach 1:
The patent performs calibration in advance in the dry state before humidity absorption occurs. This preliminary calibration establishes a baseline that remains valid even after humidity absorption, eliminating the need to wait for saturation. The system compensates for humidity effects mathematically rather than requiring physical re-calibration in humid conditions.
Solution Approach 2:
The patent skips the time-consuming humidity saturation process by calibrating in the dry state immediately. Instead of waiting for the slow saturation process (which takes several days) to complete before calibration, the method rushes through the calibration step in the dry state and then applies compensation algorithms to account for subsequent humidity absorption, dramatically reducing calibration time.
3Ease of operation
If standard calibration methods are used without considering environmental factors, then calibration process is simple and fast, but systematic errors from environmental influences like humidity cannot be corrected
Solution Approach 1:
The patent applies self-service by enabling the sensor system to automatically compensate for its own humidity-induced drift. The evaluation device calculates compensation values based on the sensor's own output variations over time, allowing the system to self-correct systematic errors without requiring complex external calibration equipment or procedures, thus maintaining simplicity while improving reliability.
Solution Approach 2:
The patent implements feedback by continuously monitoring sensor output and using this information to calculate compensation values. The system feeds back the observed drift caused by humidity absorption and applies corrective adjustments to the calibration data, creating a closed-loop system that automatically corrects environmental errors without complicating the calibration process.
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 approach effectively compensates for humidity-induced errors, ensuring sensor output values fall within tolerance ranges by correcting digital equivalent values, thereby providing precise and reliable measurements.
Implementation Method 1
The pressure applied by the engine oil is transformed in the sensor to a digital equivalent value
Implementation Method 2
a sensor characteristic is recorded by the determination of at least one measurand at at least two different temperatures
Data Source
AI summary
In a method for calibrating at least one sensor, in particular a pressure sensor, having at least one signal-conducting connection to at least one signal converter, a sensor characteristic is recorded by the determination of at least one measurand at at least two different temperatures, the extent of the influence of a further value influencing the sensor is determined from the sensor characteristic by means of a functional relation, the extent of the influence of the further influencing value is considered in the calibration and the influence of the further influencing value is balanced in the calibration. As a result, the influence of a further influencing value acting on the sensor is corrected.