Capacitive Child Seat Position Detection for Front-Rear Discrimination
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Solution Overview
Problem
Existing systems fail to accurately detect whether a child seat is positioned in a front or rear position on a vehicle seat, which is crucial for ensuring passenger safety and adapting airbag deployment strategies.
Innovation Solution
A detection system comprising a vehicle seat with a capacitive sensor attached to the backrest at a specific distance from the seat, a detection device, and a processing unit that measures capacitive values and calculates variations to determine the child seat's position based on predefined thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If capacitive sensors are used to detect child seat position, then detection capability is improved, but measurement precision is insufficient to distinguish front and rear positions
Solution Approach 1:
The backrest is divided into multiple sensing zones with capacitive sensors positioned at specific locations (first sensing zone at 30-45cm from seat, second sensing zone at 20-30cm from seat). Each zone independently measures capacitance variations, and the processing unit compares signals from different zones to distinguish front versus rear child seat positions based on the characteristic capacitance change patterns in each zone.
Solution Approach 2:
The solution transitions from single-point capacitance measurement to spatial distribution measurement by placing sensors at multiple distances from the seat along the backrest. This dimensional expansion allows the system to detect the spatial pattern of capacitance changes, which differs between front and rear child seat configurations, thereby achieving precise position discrimination.
2Measurement precision
If multiple capacitive sensors are deployed at different distances, then position detection accuracy is improved, but device complexity increases
Solution Approach 1:
Multiple capacitive sensors serve dual functions: they individually detect capacitance variations in their respective sensing zones and collectively provide spatial information for position discrimination. The same sensor array used for detecting child seat presence is also used for determining front versus rear positioning, eliminating the need for separate detection systems and reducing overall device complexity.
Solution Approach 2:
The patent combines the presence detection function and position discrimination function into a single integrated sensor system. The processing unit merges signals from multiple capacitive sensors to simultaneously determine both the presence of a child seat and its position (front or rear), reducing system complexity compared to using separate independent systems for each function.
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 effectively distinguishes between front and rear positions of child seats, enabling safer airbag deployment strategies and improved passenger safety by adapting to the child seat's position.
Implementation Method 1
a first capacitive sensor (6) with coplanar interdigital electrodes attached to the backrest (13) at a first distance from the seat; capacitive values are measured at the electrodes of the at least one first capacitive sensor
Data Source
AI summary
The present disclosure relates to a method for detecting a so-called front position or a so-called rear position of a child seat arranged on a vehicle seat; the method further comprising the following steps:a) calculating a first mean value from the capacitive values measured during a first period of the measurement phase,b) calculating a second mean value of the capacitive values measured during a second period of the measurement phase, the second period being subsequent to the first period,c) calculating a first variation between the second mean value and the first mean value,d) comparing the first variation with a first threshold,e) transmitting a first signal indicative of a detection of a forward position of the child seat, when the first variation is greater than the first threshold. The present disclosure also relates to an associated detection system.