Vehicle Seat Occupant Detection with Orientation Compensation

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Solution Overview

Problem

Existing vehicle occupant detection systems face inaccuracies in estimating occupant weight due to changes in seat orientation angle and vehicle movement, leading to errors in distinguishing between adults and children, which can result in inappropriate airbag deployment.

Innovation Solution

A weight-based occupant detection device installed in a vehicle seat, comprising a weight sensing means and a seat orientation angle sensing means, which outputs a weight signal and an orientation angle signal to compensate for seat tilt and vertical acceleration, enabling accurate occupant weight estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a weight sensing means is installed in a vehicle seat to estimate occupant weight, then occupant detection capability is improved, but measurement precision deteriorates due to seat orientation angle changes and vehicle movement

Engineering Contradiction:

Improveoccupant detection capabilityVSAvoidoccupant weight estimation accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

An orientation angle sensing means is introduced as an intermediary element to detect seat orientation changes. This mediator provides additional information about seat tilt and vehicle movement, which is then used to compensate for measurement errors in the weight sensing means, thereby maintaining measurement precision while preserving occupant detection capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system compensates for measurement errors by dynamically adjusting the weight estimation based on changes in seat orientation parameters. When the seat orientation angle changes, the system calculates compensation values and applies them to the raw weight signal, effectively correcting the measurement precision without requiring physical modification of the weight sensing means

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If seat orientation angle changes are used to compensate weight signals, then measurement precision is improved, but device complexity increases due to additional sensing means and compensation processing

Engineering Contradiction:

Improveoccupant weight estimation accuracyVSAvoiddetection system structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The orientation angle sensing means serves multiple functions: it detects seat tilt angle, determines vehicle movement effects, and provides data for compensation calculations. This multi-functionality reduces the need for separate specialized sensors for each detection purpose, thereby limiting the increase in device complexity while achieving improved measurement precision

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If weight sensing means is installed to distinguish adults from children, then occupant classification capability is improved, but measurement precision deteriorates due to heave motion and weight off-loading effects

Engineering Contradiction:

Improveoccupant classification capabilityVSAvoidweight measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system implements a feedback mechanism where the orientation angle sensing means continuously monitors seat orientation and vehicle movement, and this information is fed back to adjust the weight estimation in real-time. This feedback loop compensates for heave motion and weight off-loading effects, maintaining measurement precision while preserving the ability to distinguish adults from children

Inventive Principle:

Principle #23Feedback

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 solution provides accurate occupant weight estimation, reducing errors by up to 10% and ensuring proper airbag deployment by distinguishing between adults and children, even during vehicle movements and seat adjustments.

Implementation Method 1

a weight sensing means (18) installed in a vehicle seat (10) in a manner effective to sense weight on a seating surface (14) of the vehicle seat (10)

Methodology Applied

Scientific EffectWeight sensing: Force

Implementation Method 2

a seat orientation angle sensing means (36) configured to output an orientation angle signal indicative of a seat orientation angle

Methodology Applied

Scientific EffectOrientation sensing: Gravitation

Data Source

PatentUS8558713B2Weight based vehicle seat occupant detection device with compensation for seat orientation angle

Publication Date: 2013.10.15 APTIV TECHNOLOGIES AG

AI summary

A weight based occupant detection device that includes a weight sensing device installed in a vehicle seat in a manner effective to sense weight on a seating surface. The weight sensing device is configured to output a weight signal indicative of an occupant weight of a seat occupant residing on the vehicle seat. The occupant detection device also includes a seat orientation angle sensing device that is configured to output an orientation angle signal indicative of a seat orientation angle. The occupant detection device may also include an accelerometer for sensing vertical acceleration of the vehicle seat, and a seat backrest angle device for measuring the angle of the seat backrest. The occupant detection device compensates a signal from the weight sensing device for errors caused by seat orientation, seat vertical acceleration and seat backrest angle.