Sitting Sensor Grid Layout for Forward and Rearward Position Detection

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Solution Overview

Problem

Existing sitting sensors fail to accurately detect sitting positions where the occupant shifts forward or backward from the normal position, as they rely on linearly disposed pressure-sensitive switches that only register when multiple contacts are activated, missing cases where only one contact is turned on due to the shifted posture.

Innovation Solution

A sitting sensor design featuring a pair of insulating sheets with pressure-sensitive switches configured in groups along the left-right and front-rear directions of a seat, with specific switches positioned at ends to detect loads dispersed in these directions, ensuring accurate detection even when the occupant sits at forward or rearward positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If pressure-sensitive switches are linearly disposed with predetermined space apart, then the device complexity is reduced and manufacturing is simplified, but the measurement precision deteriorates when the occupant sits at forward or rearward positions

Engineering Contradiction:
Improveconfiguration complexityVSAvoidsitting detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from a single linear arrangement of pressure-sensitive switches to a two-dimensional grid arrangement. The switches are disposed in multiple rows along the front-rear direction and multiple columns along the left-right direction, creating a planar detection surface that covers various sitting positions more comprehensively

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The detection area is segmented into multiple independent pressure-sensitive switch units arranged in a grid pattern. Each switch acts as an independent detection element, and the collective arrangement of these segmented elements provides comprehensive coverage of different sitting positions including forward and rearward shifts

Inventive Principle:
Principle #1Segmentation

2Reliability

If multiple contacts are required to be turned on for sitting detection, then false detection is reduced, but the reliability deteriorates when only one contact is activated due to shifted sitting position

Engineering Contradiction:
Improvedetection reliabilityVSAvoidpositional adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent adds spatial dimensionality to the detection system by arranging switches in both front-rear and left-right directions. This multi-dimensional arrangement ensures that regardless of how the occupant shifts position, at least two switches in different spatial relationships will be activated, maintaining reliable detection across various sitting postures

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The grid arrangement of pressure-sensitive switches creates a universal detection system that handles multiple sitting scenarios simultaneously. The same switch configuration effectively detects normal sitting, forward shifting, rearward shifting, and lateral movements, making the system adaptable to various occupational behaviors without requiring separate detection mechanisms

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 sensor effectively detects sitting by preventing relative displacement of pressure-sensitive switches and enhancing sensitivity, allowing for appropriate detection of sitting regardless of the occupant's posture, thereby improving upon existing technologies.

Implementation Method 1

a plurality of pressure-sensitive switches including a pair of electrodes facing each other at the plurality of openings

Methodology Applied
Scientific EffectPressure-sensitive switch detection: Piezoresistive Effect

Data Source

PatentEP3780051B1Sitting sensor
Publication Date: 2023.10.04 FUJIKURA LTD
  • EP3780051B1 patent drawingFigure 1
  • EP3780051B1 patent drawingFigure 2
  • EP3780051B1 patent drawingFigure 3~4

AI summary

A plurality of pressure-sensitive switches of a sitting sensor (1) has a first pressure-sensitive switch group including at least one first pressure-sensitive switch (SW11) including a first specific pressure-sensitive switch and at least one second pressure-sensitive switch (SW21), and a second pressure-sensitive switch group including at least one first pressure-sensitive switch (SW11, SW12) including a first specific pressure-sensitive switch, and at least one second pressure-sensitive switch (SW22), in which in the first pressure-sensitive switch group, the first pressure-sensitive switch (SW11) and the second pressure-sensitive switch (SW21) are disposed adjacent to each other along a left-right direction of a seat (SE), in the second pressure-sensitive switch group, the first pressure-sensitive switches (SW11, SW12) and the second pressure-sensitive switch (SW22) are disposed adjacent to each other along a front-rear direction of the seat (SE), and turning on at least one first pressure-sensitive switch and at least one second pressure-sensitive switch causes a current to flow between a pair of terminals (T1, T2).