Seat occupancy sensor
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Solution Overview
Problem
Existing seat occupancy sensors in vehicles face challenges in distinguishing between an occupant and a box-shaped object, particularly due to varying pressure distributions caused by different postures of the occupant and the linear pressure distribution from box-shaped objects, which complicates accurate detection.
Innovation Solution
A seat occupancy sensor system with pairs of switch modules, each comprising first, second, and third pressure-sensitive switches, configured to turn on when at least one of the first and second switches and the third switch are activated, allowing for detection of occupant presence regardless of posture or the presence of a box-shaped object, with the switches connected in specific parallel and series configurations for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pressure-sensitive switches are arranged in the fore-and-aft direction to detect occupant presence, then the detection coverage is improved, but the ability to distinguish between an occupant and a box-shaped object deteriorates
Solution Approach 1:
The seating area is divided into multiple detection regions with pressure-sensitive switches arranged in the fore-and-aft direction. Each switch monitors a specific segment, allowing the system to detect pressure distribution patterns along the longitudinal axis and distinguish occupants from box-shaped objects based on their distinct pressure signatures.
Solution Approach 2:
The detection system transitions from simple presence detection to two-dimensional pressure distribution analysis by arranging switches in the fore-and-aft direction. This dimensional expansion enables the system to differentiate between occupants (who exert pressure across multiple regions) and box-shaped objects (which concentrate pressure in specific areas).
2Adaptability or versatility
If pressure-sensitive switches are arranged to cover various occupant postures, then the adaptability to different postures is improved, but the device complexity increases
Solution Approach 1:
The seating area is segmented into multiple detection zones along the fore-and-aft direction, with each zone monitored by pressure-sensitive switches. This segmentation allows the system to adapt to various occupant postures by detecting pressure patterns across different segments, whether the occupant is seated upright, reclined, or in intermediate positions.
Solution Approach 2:
The pressure-sensitive switch array serves multiple functions: detecting occupant presence, determining occupant posture, and distinguishing occupants from objects. By arranging switches in the fore-and-aft direction, the same hardware configuration handles diverse detection tasks without requiring additional specialized sensors for each function.
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
The system effectively differentiates between an occupant and a box-shaped object, accurately detecting seating regardless of the occupant's posture or the object's orientation, while simplifying the configuration through electrical connections of pressure-sensitive switches.
Implementation Method 1
a first pressure-sensitive switch (16A, 17A, 18A, 19A) and a second pressure-sensitive switch (16B, 17B, 18B, 19B) that are disposed on a front part so as to be laterally spaced from each other and a third pressure-sensitive switch (16C, 17C, 18C, 19C) disposed on a rear part
Data Source
AI summary
To provide a seat occupancy sensor for detecting a seated occupant, a seat occupancy sensor provided in a vehicle seat includes a pair of switch modules disposed in an occupant seating area of a seat cushion, wherein: each of the switch modules includes a first pressure-sensitive switch and a second pressure-sensitive switch that are disposed on a front part so as to be laterally spaced from each other and a third pressure-sensitive switch disposed on a rear part; each of the switch modules is configured to be turned on when at least one of the first pressure-sensitive switch and the second pressure-sensitive switch is on and the third pressure-sensitive switch is on; and the seat occupancy sensor is configured to be turned on when the switch modules are both on.