Occupant Detection System Temperature Correction
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Solution Overview
Problem
Existing occupant detection systems face challenges in accurately determining the sitting condition on a vehicle seat due to temperature fluctuations, which can lead to incorrect weight measurements and unstable determination of the occupant's presence, especially when temperature changes abruptly.
Innovation Solution
An occupant detection system comprising load detection means, temperature detection means, and correction means that deducts the time change amount of the load when the temperature change is significant, and stops determination when temperature changes abruptly, using multiple load and temperature sensors to stabilize the measurement and reduce fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is integrated with the load sensor to correct load fluctuation due to temperature variation, then the correction capability is improved, but when temperature changes abruptly, the temperature difference between the temperature sensor and strain gauge causes inaccurate correction
Solution Approach 1:
The patent divides the temperature correction process into two distinct parts: (1) a temperature correction value calculated based on temperature change amount and predetermined coefficients, and (2) a load fluctuation correction value calculated based on the difference between actual load change and temperature-induced load change. This segmentation allows each correction component to address specific sources of error independently, improving overall correction accuracy during abrupt temperature changes.
Solution Approach 2:
The patent introduces predetermined first and second coefficients as intermediary parameters that mediate between temperature change and load correction. These coefficients represent the relationship between temperature variation and load sensor output, allowing the system to calculate temperature-induced load changes without requiring direct measurement of strain gauge temperature, thus avoiding the temperature gradient problem.
2Measurement precision
If the detected load is corrected based on temperature change using previously stored information, then correction is attempted, but when the sitting position or posture of the occupant affects the positional relationship with the air conditioner, the previously stored information becomes unsuitable and load correction accuracy deteriorates
Solution Approach 1:
The patent makes the correction system dynamic by calculating correction values based on real-time temperature change amount rather than relying on previously stored information. The first coefficient is determined based on the actual temperature change rate, allowing the system to adapt to different thermal conditions and occupant configurations dynamically, rather than using fixed lookup tables that may become obsolete.
Solution Approach 2:
The patent changes the correction approach from using fixed previously stored information to calculating correction values based on current temperature change parameters. By using the actual temperature change amount and predetermined coefficients to calculate the temperature correction value, the system adapts to varying sitting positions and postures without requiring pre-stored data for each configuration.
3Productivity
If the sitting condition is determined based on load data, then the determination process is simple, but when temperature changes abruptly causing load fluctuation, the sitting condition cannot be determined accurately
Solution Approach 1:
The patent performs preliminary correction of the load value by subtracting the temperature correction value from the detected load before determination. This preliminary action removes the temperature-induced error component from the load measurement, ensuring that the subsequent sitting condition determination is based on accurate load data even during abrupt temperature changes, without adding significant processing complexity.
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 configuration ensures accurate determination of the sitting condition by eliminating load fluctuations caused by temperature changes and preventing unnecessary determinations, thereby improving the reliability of the system.
Implementation Method 1
a load detection means capable of detecting a load placed on a seat
Implementation Method 2
a temperature detection means capable of detecting a temperature and located adjacent to the load detection means
Data Source
AI summary
A load detector is capable of detecting a load placed on a seat. A temperature detector is capable of detecting a temperature and located adjacent to the load detector. A correction controller corrects the load detected by the load detector in such a way as to deduct a time change amount of the load from the detected load when a time change amount of the temperature detected by the temperature detector is larger than a predetermined threshold value of the time change amount of the temperature and the time change amount of the load detected by the load detector is smaller than a predetermined threshold value of the time change amount of the load. A determination controller determines a sitting condition on the seat based on the corrected load.