Vehicle Seat Thermistor Occupant Classification
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Solution Overview
Problem
Current safety systems for vehicles struggle to accurately distinguish between adult and child passengers, as well as between children in child restraint systems and booster seats, which affects the effectiveness of safety measures.
Innovation Solution
A temperature-based classification system using thermistors and reference sensors embedded in vehicle seat cushions and backs, which detect heat transfer and compute the magnitude and rate of temperature change to differentiate between adult, child in a CRS, and child in a booster seat passengers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional resistors or simple temperature sensors are used, then device complexity is reduced, but measurement precision and temperature sensitivity are insufficient to distinguish between different occupant types
Solution Approach 1:
The patent uses thermistors whose resistance changes with temperature to detect subtle thermal differences between occupant types. By monitoring resistance variations caused by different heat transfer rates, the system achieves high measurement precision without complex sensor arrays. The thermistor's inherent temperature-dependent resistance provides the necessary sensitivity to distinguish between adults, children in CRS, and children in booster seats.
2Measurement precision
If multiple complex sensors are deployed to distinguish between adult, child in CRS, and child in booster seat, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent divides the seat into multiple thermal zones with thermistors positioned at different locations (seat cushion, seat back, headrest) to detect heat transfer patterns. By analyzing temperature variations across these segmented zones over time, the system can distinguish between different occupant types using simple temperature measurements rather than complex sensor arrays. The segmentation of thermal measurement points provides classification capability through pattern recognition.
Solution Approach 2:
The patent replaces complex mechanical or electronic classification systems with a thermal-based detection approach. Instead of using multiple sensors measuring force, position, or electrical properties, the system uses thermistors to measure temperature changes caused by different occupant thermal characteristics. This substitution of measurement modality simplifies the overall system while maintaining high classification accuracy.
3Measurement precision
If existing classification systems are used, then device complexity is maintained, but measurement precision and granularity for distinguishing child seat types are insufficient
Solution Approach 1:
The patent monitors temperature changes over time rather than relying on static temperature measurements. By tracking the dynamic thermal response as the occupant settles into the seat and heat transfers occur, the system can distinguish between different occupant types based on their unique thermal profiles. The temporal dimension of temperature measurement provides additional discrimination capability without requiring more sensors.
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 solution provides a cost-effective and less complex method to accurately classify passenger types, enhancing the robustness and granularity of existing safety systems by integrating new algorithms with existing vehicle technologies.
Implementation Method 1
The temperature sensors are used to detect heat transfer between an object in contact with the cushion through the seat trim and, if applicable, some amount of seat comfort base material such as foam
Implementation Method 2
Because the resistance of a thermistor varies with temperature more than conventional resistors, this type of resistor is thus highly sensitive to changes in local temperatures
Data Source
AI summary
A thermistor-based system and method for distinguishing between adult and child passengers and, of the child passengers, between those seated in a child restraint system and those seated in a child booster is provided. The disclosed inventive concept includes at least one classification thermistor/temperature sensing device, at least one reference thermistor, an algorithm to compute and classify conditions, and related wiring and hardware. The classification thermistor/temperature sensing device is located in a seat cushion assembly and a seat back. The temperature sensors are used to detect heat transfer between an object in contact with the cushion through the seat trim and, if applicable, some amount of seat comfort base material. The reference thermistor may be provided to enhance robustness of classification determination. The algorithm computes and classifies conditions based on at least the magnitude and/or the rate of temperature change between the classification sensor and the reference sensor.