Vehicle Seat Occupancy Detection via Load Rate Analysis
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Solution Overview
Problem
Existing seat occupancy determination methods for vehicles, based solely on load sensors, can mistakenly identify a child seat as an adult due to temporary large loads during seatbelt engagement, leading to inaccurate airbag deployment control, especially when cost reduction measures are implemented.
Innovation Solution
An apparatus and method that includes load detecting portions and seatbelt buckling detecting portions to differentiate between adult and child seat occupancy by analyzing the speed and pattern of load changes around the time of seatbelt engagement, determining the mounted state of a child seat through specific load increase and decrease patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If load sensors are used to determine seat occupancy, then seat occupancy can be detected, but false detection of adult occupancy when child seat is mounted occurs due to temporary large loads during seatbelt engagement
Solution Approach 1:
The system transitions from static load threshold comparison to dynamic load change rate analysis. By monitoring the rate of load change (dW/dt) rather than just absolute load values, the system can distinguish between temporary load spikes during seatbelt engagement and actual adult occupancy, resolving the false detection issue while maintaining detection accuracy
Solution Approach 2:
The system implements feedback by continuously monitoring load changes and comparing them against predefined thresholds and time conditions. The determination unit uses feedback from the load sensor data, combined with seatbelt buckle status, to dynamically adjust occupancy determination, preventing false positives while maintaining reliable detection
2Ease of manufacture
If the number of load sensors is reduced for cost reduction, then manufacturing cost decreases, but accurate determination of seat occupancy becomes difficult
Solution Approach 1:
The system changes the parameters used for occupancy determination from static load thresholds to dynamic load change rates combined with temporal analysis. By analyzing the rate of load change (dW/dt) and the duration of load conditions, the system maintains high detection accuracy with fewer sensors, as the dynamic characteristics provide additional discrimination capability without requiring more sensor elements
Data Source
AI summary
An apparatus for determining a seat occupancy includes a load detecting portion attached to a seat portion of a seat for a vehicle and detecting a seat occupancy load, a seatbelt buckling detecting portion detecting an engagement of a buckle of a seatbelt, and a seat occupancy determining portion determining the seat occupancy on the basis of detection signals from the seatbelt buckling detecting portion and the load detecting portion. The seat occupancy determining portion determines a mounted state of a child seat, in which the child seat is placed on the seat and is fixed thereto by means of the seatbelt, in a case where the seat occupancy load changes so as to be increased at a predetermined speed or faster and subsequently so as to be decreased at a predetermined speed or faster, within a time period proximate to a time point when the buckle is engaged.