Core Temperature Estimation Using Dynamic Thermal Resistance Calibration
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Solution Overview
Problem
Existing methods for estimating core body temperature suffer from estimation errors due to individual differences and variations in thermal resistance and blood flow, leading to inaccuracies.
Innovation Solution
A method involving multiple thermal resistance members and sensors to measure and normalize surface temperatures, derive a temperature wave arrival time, and calculate a proportionality coefficient based on thermophysical properties to correct for individual differences and blood flow variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a constant proportionality coefficient A is used for temperature estimation, then the device complexity is reduced and ease of operation is improved, but measurement precision deteriorates due to individual differences and blood flow variations
Solution Approach 1:
The patent transforms the static, constant proportionality coefficient into a dynamic coefficient that adapts to individual differences and physiological changes. By measuring thermal resistance characteristics specific to each person and updating the coefficient accordingly, the system achieves higher measurement precision without requiring complex real-time adjustment mechanisms during temperature estimation.
Solution Approach 2:
The patent performs preliminary measurement of thermal resistance characteristics (RB, RS, RA) before actual temperature estimation. These pre-measured values are used to calculate an optimized proportionality coefficient A that is specific to each individual. This preliminary calibration approach allows the system to achieve high precision in subsequent temperature estimations without adding complexity to the real-time estimation process.
2Measurement precision
If thermal resistance values are measured and used to adjust the proportionality coefficient, then measurement precision is improved, but the device complexity increases due to additional sensors and measurement steps
Solution Approach 1:
The patent combines multiple measurement functions into a single integrated sensor system. The same sensor that measures skin temperature is also used to measure thermal resistance characteristics by analyzing temperature changes over time. This merging of functions eliminates the need for separate thermal resistance sensors, thereby improving measurement precision while avoiding additional device complexity.
Solution Approach 2:
The patent makes the temperature sensor multi-functional by using it for both direct temperature measurement and indirect thermal resistance measurement. By analyzing the temporal characteristics of temperature measurements, the sensor simultaneously provides information about thermal resistance, making the system more precise without requiring dedicated thermal resistance measurement devices.
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
Reduces estimation errors by dynamically adjusting the proportionality coefficient, thereby improving the accuracy of internal temperature estimation.
Implementation Method 1
measuring a temperature of a first thermal resistance member provided with a first temperature sensor by the first temperature sensor
Implementation Method 2
measuring a temperature of a surface of a test subject by the first temperature sensor after the first thermal resistance member and the first temperature sensor come into contact with the test subject
Implementation Method 3
measuring a temperature of a surface of a test subject by a second temperature sensor provided on a surface of a second thermal resistance member on a test subject side
Implementation Method 4
measuring a temperature at a position away from the test subject by a third temperature sensor provided on a surface of the second thermal resistance member on a side opposite to the surface on the test subject side
Data Source
AI summary
A temperature estimation method includes bringing a first thermal resistance member into contact with the test subject, measuring a first temperature of a surface of the test subject, calculating a temperature normalized by an instantaneous value of the first temperature of the surface of the test subject and the temperature of the first thermal resistance member and a setting value of the temperature of the surface of the test subject, deriving, as a temperature wave arrival time, deriving a proportionality coefficient based on the temperature wave arrival time, measuring a second temperature of the surface of the test subject, measuring a third temperature of a surface of the second thermal resistance member on a side opposite to the surface on the test subject side, and calculating an internal temperature of the test subject based on the second temperature, the third temperature, and the proportionality coefficient.