Vehicle Occupant Decision Device with Buckle Load Threshold
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Solution Overview
Problem
Conventional occupant decision devices for vehicles face complexity and increased calculation time in determining the type of occupant on a vehicle seat, leading to reduced accuracy due to the need to calculate left-right load differences and accumulate errors from load sensor detection values.
Innovation Solution
An occupant decision device with load detecting bodies for seat loads, a seat belt wearing detection mechanism to prevent erroneous adult decisions when a child seat is attached, and a buckle load calculation to change the decision to a child seat attachment based on engagement and buckle load thresholds, eliminating the need for left-right load difference calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If left-right difference load value calculation is used to decide child seat attachment, then decision accuracy is improved, but calculation complexity and time are increased
Solution Approach 1:
The patent extracts the essential decision criterion from complex left-right difference calculations to a simpler buckle load threshold comparison. By focusing only on the buckle load value and comparing it against a predetermined threshold, the system eliminates unnecessary calculation steps while maintaining the ability to accurately detect child seat attachment states.
Solution Approach 2:
Instead of calculating the difference between left and right load values to detect child seat attachment, the patent inverts the approach by directly measuring the buckle load and comparing it to a threshold. This inversion simplifies the decision logic from a multi-step calculation to a single threshold comparison.
2Measurement precision
If left-right difference load value calculation is used to decide child seat attachment, then decision accuracy is improved, but calculation time is increased
Solution Approach 1:
The patent extracts the essential decision criterion from complex left-right difference calculations to a simpler buckle load threshold comparison. By focusing only on the buckle load value and comparing it against a predetermined threshold, the system eliminates unnecessary calculation steps while maintaining the ability to accurately detect child seat attachment states.
Solution Approach 2:
The patent skips the intermediate step of calculating left-right load differences and directly compares the buckle load to a threshold. This rushing through the decision process reduces calculation time while maintaining accuracy, as the system jumps directly to the critical comparison point.
3Measurement precision
If load sensor detection values are used for occupant classification, then measurement capability is provided, but error accumulation occurs
Solution Approach 1:
The patent introduces the buckle load as an intermediary measurement that mediates between the load sensors and the final occupant classification decision. By using the buckle load (which reflects the tightening force on the child seat) as the primary decision criterion, the system avoids directly using load sensor values that are prone to error accumulation, thus improving reliability.
Data Source
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AI summary
Load sensors 4FR, 4RR, 4FL, 4RL are disposed on four corners of a seat cushion. An occupant decision section 51 of an occupant detection ECU 5 decides a type of an occupant BH on a vehicle seat based on loads Wfr to Wrl detected by the load sensors 4FR to 4RL. A CRS changing section 53 that prohibits the occupant decision section 51 from changing a decision to a decision result that an adult is seated in the vehicle seat and changes the decision to a decision result that a child seat is attached on the vehicle seat when an engagement of a tongue plate with a buckle of a seat belt device is detected by a buckle switch 3 and a buckle load Wb calculated by buckle load calculation section 54 is less than a predetermined buckling load threshold Wbth1, Wbth2 in a case where the occupant decision section 51 decides that an adult is seated in the vehicle seat.