Occupant Load Sensor Classification for Vehicle Airbag Control
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Solution Overview
Problem
Existing occupant determination systems for vehicles face issues with incorrect classification of occupants due to posture changes and fluctuations in detected load, leading to delayed inter-class transitions and inappropriate airbag control.
Innovation Solution
An occupant determination apparatus using a load sensor and determination section that classifies occupant loads into multiple classes based on threshold loads, allowing inter-class transitions when the detected load remains within specific threshold values for defined times, enabling minimal and reliable transitions even with fluctuating loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of occupant classes is increased to improve classification precision, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the occupant classification into multiple distinct classes (vacant seat, child, small adult, large adult) with specific threshold ranges for each. By dividing the continuous load spectrum into discrete segments, the system achieves precise classification without requiring complex continuous analysis algorithms.
Solution Approach 2:
The patent uses parameter changes by adjusting threshold values and class definitions based on statistical analysis of load data. The determination section dynamically modifies classification parameters to adapt to different vehicle types and seat positions, improving precision without increasing hardware complexity.
2Device complexity
If fixed threshold values are used for class determination, then device complexity is reduced, but reliability deteriorates due to incorrect determination during posture changes
Solution Approach 1:
The patent implements dynamic threshold adjustment where the determination section modifies threshold values based on detected load patterns and occupancy duration. Instead of fixed thresholds, the system adapts thresholds in real-time to distinguish between temporary posture changes and genuine occupancy state changes, significantly improving reliability.
Solution Approach 2:
The system incorporates feedback mechanisms where the determination section continuously monitors load sensor output and adjusts class determination based on the duration and pattern of threshold crossings. This feedback loop allows the system to filter out transient fluctuations and make more reliable occupancy decisions.
3Reliability
If accumulated time period is used for inter-class transition determination, then reliability is improved, but speed of response deteriorates
Solution Approach 1:
The patent applies partial action by using different accumulation time periods for different types of transitions. For high-confidence transitions (clear threshold crossings), the system requires shorter accumulation times, while for ambiguous cases, longer accumulation periods are used. This selective approach balances speed and reliability.
Solution Approach 2:
The determination section segments the transition determination process into multiple stages with different time requirements. Immediate transitions are permitted for clear-cut cases, while gradual transitions use accumulated time verification. This segmentation allows the system to respond quickly when certain and take more time when uncertain.
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
Ensures proper airbag control by minimizing incorrect determinations and allowing timely inter-class transitions, ensuring accurate classification and protection of occupants during vehicle entry and exit, and varying load conditions.
Implementation Method 1
a load sensor to detect a load of an occupant who is seated in a seat of a vehicle to provide the detected load as a load signal
Data Source
AI summary
An occupant determination apparatus includes a load sensor and a determination section. The load sensor detects a load of an occupant seated in a seat of a vehicle to provide the detected load as a load signal. The determination section determines presence or absence of the occupant and a physical size of the occupant by classifying the load signal into a subject class among a plurality of classes that are ordered from small to large according to the physical sizes based on predetermined threshold loads. The subject class is stored as a determined class. The determination section permits the determined class to transition from a present class to an immediately adjacent larger class when the load signal equal to or larger than a threshold load between the present class and the immediately adjacent larger class continues being received for a threshold time.