Vehicle Seat Occupant Classification via Dual-Zone Capacitive Sensing
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Solution Overview
Problem
Current occupant classification systems in vehicles often misclassify electronic devices as occupants, leading to inappropriate deployment of airbags and seat belt reminders.
Innovation Solution
The system employs capacitive sensing using electrodes in the seat bottom and back, with a controller to differentiate between occupants and objects by analyzing impedance measurements, and includes a secondary threshold and integration of seat back heater data to improve classification accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the seat bottom heater is used to determine occupant classification, then the system can detect occupant presence, but electronic devices cause misclassification leading to incorrect airbag deployment decisions
Solution Approach 1:
The patent divides the seat into multiple sensing zones: seat bottom heater region and seat back heater region. By segmenting the detection areas and analyzing impedance differences between regions, the system can distinguish between electronic devices (which typically only affect seat bottom) and actual occupants (affect both seat bottom and seat back), thereby resolving the misclassification problem
Solution Approach 2:
The patent introduces a dual-sensing mechanism using both seat bottom heater and seat back heater as intermediary detection elements. The seat back heater acts as an additional verification layer that mediates the classification decision, preventing false positives from electronic devices and improving overall classification reliability
2Ease of operation
If the seat back heater algorithm uses occupancy classification status to control seat belt reminder, then the system can coordinate safety features, but electronic devices still cause incorrect seat belt reminder activation
Solution Approach 1:
The patent segments the detection system into seat bottom and seat back regions with separate impedance analysis. This segmentation allows the system to cross-validate readings and distinguish electronic devices from occupants, improving object presence classification accuracy while maintaining seat belt reminder coordination
Solution Approach 2:
The patent implements a feedback mechanism where the seat back heater measurement feeds into the classification algorithm to verify or override seat bottom heater readings. This feedback loop corrects misclassifications caused by electronic devices, ensuring accurate seat belt reminder activation based on true occupant presence
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 approach reduces misclassifications, providing more accurate occupant classification and proper activation/deactivation of safety systems, especially in cases involving electronic devices and varying occupant positions.
Implementation Method 1
The system employs capacitive sensing using electrodes in the seat bottom and back, with a controller to differentiate between occupants and objects by analyzing impedance measurements
Implementation Method 2
Current occupant classification systems use the seat bottom heater to determine occupant classification. Similar to the seat bottom heater, the seat back heater also has two regions.
Data Source
AI summary
An occupant classification system that includes a first sensing electrode located in a bottom of a vehicle seat and a second sensing electrode located in a back of the vehicle seat. The system includes a controller that is configured to control the supply of a first signal to the first electrode and a second signal to the second electrode. A measurement circuit is provided that is configured to measure a first property of the first signal and second property of the second signal. The controller is configured to classify an occupant using the first and second properties.