Vehicle Seat Capacitive Sensing for Occupant Trunk Rotation Detection
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Solution Overview
Problem
Current methods for detecting inappropriate sitting postures in vehicles, which can lead to lower back pain, are not robust or reliable, necessitating a more effective monitoring solution.
Innovation Solution
A method utilizing at least two interdigitated capacitive sensors on a vehicle seat, connected to a controller that measures capacitive values to determine stationary postures and detect rotations of the occupant's trunk, generating a detection signal based on defined variation ranges, and optionally warning the occupant or managing airbag deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional posture detection methods are used, then detection capability is provided, but reliability and robustness are insufficient
Solution Approach 1:
The detection system segments the trunk into multiple zones (upper trunk, lower trunk, pelvis) and uses separate capacitive sensors for each zone. This segmentation allows independent measurement of rotation in different regions, improving both reliability through multiple measurement points and precision through zone-specific detection thresholds
Solution Approach 2:
The patent combines multiple capacitive sensors into a single integrated detection system that measures rotations at different trunk levels simultaneously. The controller merges data from all sensors to determine overall trunk rotation, enhancing reliability through redundant measurement and precision through comparative analysis of multiple sensor readings
2Measurement precision
If more complex detection systems are implemented, then detection accuracy improves, but system cost increases
Solution Approach 1:
The patent replaces complex mechanical posture detection systems with capacitive sensing technology. Capacitive sensors measure changes in electrical capacitance caused by trunk rotation, eliminating the need for mechanical linkages, joints, or physical contact points. This substitution maintains high measurement precision while dramatically reducing manufacturing complexity and cost
Solution Approach 2:
The system changes the measurement parameter from mechanical displacement to electrical capacitance. By detecting capacitance variations caused by trunk rotation rather than using mechanical position sensors, the system achieves precise rotation detection with simpler, less expensive components that are easier to manufacture and integrate into the seat
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 provides a more reliable and cost-effective detection of occupant posture, effectively preventing lower back pain by accurately identifying rotations of the thorax and pelvis, and potentially triggering safety measures.
Implementation Method 1
at least two interdigitated capacitive sensors mounted on the seat... periods during which capacitive values are measured by the capacitive sensors
Data Source
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AI summary
The invention relates to a method of detecting a rotation of a part of the trunk of an occupant sitting on a seat (4) of a vehicle by at least two capacitive sensors (C1, C2, C3, C4, C5) carried by the seat, the method comprising the following steps: - triggering (30) of measurement of capacitive values;- determine (32,34,36,38,40,42) from the capacitive values measured successively, a first stationary posture of the occupant during a first stationary period, a movement of a part of the occupant's trunk, and a second stationary posture of the occupant during a second stationary period, - calculate (44, 46) for each capacitive sensor, the variation between the capacitive values measured during the first stationary period and the capacitive values measured during the second stationary period, - if the variation calculated for the capacitive sensors is within ranges of capacitive values defined for said capacitive sensors, generate (50) a detection signal.;