Capacitive Seat Occupancy Detection Using Compressible Dielectric Spacers
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Solution Overview
Problem
Existing seat occupancy detection systems lack precision and sensitivity in determining the presence of an occupant, particularly in vehicle seats, as they fail to effectively combine weight and capacitive sensing for accurate classification.
Innovation Solution
A capacitive sensing system integrated with weight sensing, utilizing multiple electrodes on opposite sides of a spacer layer with compressible dielectric material, where the capacitance between conductive layers is monitored to detect the presence of an occupant using a sensing circuit and controller, allowing for precise measurement and calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional weight sensing alone is used for seat occupancy detection, then the system structure is simple, but the measurement precision and sensitivity are insufficient
Solution Approach 1:
The patent combines weight sensing and capacitive sensing into a single integrated system. The sensing mat includes both weight-sensitive elements and capacitive electrodes that work together to detect occupancy, providing both the structural support function and the detection function through one component, thereby improving measurement precision without proportionally increasing system complexity
Solution Approach 2:
The sensing mat serves multiple functions simultaneously: it provides structural support for the seat, detects occupancy through weight sensing, and detects occupancy through capacitive sensing. This multi-functionality allows the system to achieve high measurement precision while maintaining relatively simple overall structure
2Measurement precision
If multiple sensing components are added to improve detection accuracy, then the measurement precision improves, but the system thickness increases making it more intrusive in seat design
Solution Approach 1:
The patent merges weight sensing and capacitive sensing into a single integrated sensing mat structure. The capacitive electrodes are embedded within the same mat that provides weight sensing, eliminating the need for separate layered components and thereby maintaining thin profile while achieving improved detection precision through combined sensing mechanisms
Solution Approach 2:
The capacitive electrodes are nested within the structure of the weight sensing mat. The sensing mat is constructed with multiple layers where capacitive elements are integrated into the same structural assembly as the weight-sensitive elements, creating a compact nested configuration that minimizes overall thickness
3Adaptability or versatility
If capacitive sensing is added to weight sensing, then the adaptability and classification capability improve, but the device complexity increases
Solution Approach 1:
The patent combines capacitive sensing and weight sensing circuits into an integrated sensing system where both sensing modalities are processed together. The controller receives signals from both capacitive electrodes and weight-sensitive elements, combining the data to provide comprehensive occupant classification capabilities including detection of occupant type, position, and weight
Solution Approach 2:
The sensing system is designed to perform multiple detection functions through a unified architecture. The same sensing mat and controller handle both weight measurement and capacitive measurement, providing universal processing capability that improves adaptability for different occupancy scenarios without requiring separate dedicated systems for each sensing type
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 provides accurate and sensitive detection of seat occupancy by combining capacitive and weight sensing, enabling effective classification of occupant presence with reduced development costs and system thickness, making it less intrusive in seat design.
Implementation Method 1
a sensing circuit operatively coupled to the first and second conductors and configured to sense the presence of an object using a measure of the capacitance between the first and second conductors
Implementation Method 2
The layers are separated by a compressible spacer. The compressible spacer preferably includes a plurality of nodes of dielectric material
Data Source
AI summary
A capacitive detection system including an upper electrode printed on an upper film layer and a lower electrode printed on a lower film layer. The system includes a plurality of nodes of dielectric material printed in a spaced apart pattern on the lower film layer. The upper film layer is positioned over the lower film layer so that when a downward force is applied to the upper film layer the distance between at least a portion of the upper conductor and the lower conductor decreases. The system includes a controller operatively connected to the upper and lower electrodes. The controller includes a sensing circuit or processor configured to detect the presence of the occupant using a measure of the capacitance between the upper and lower electrode.