Vehicle Seat Occupant Detection Threshold Logic
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Solution Overview
Problem
Existing occupant determining devices in vehicles face issues with delayed state switching due to temporary load variations from occupant posture changes, leading to incorrect and prolonged occupant type determinations.
Innovation Solution
The implementation of a controller that sets multiple determination thresholds and corresponding delaying times, where larger thresholds have shorter delaying times, allowing for immediate and accurate determination of an adult occupant based on load applied to the seat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a low-pass filter or delaying transaction is applied to prevent frequent switching of occupant determination state, then the stability of occupant determination is improved, but the response speed to actual occupant state changes is reduced
Solution Approach 1:
The patent applies dynamics by making the delaying time variable rather than fixed. The controller dynamically adjusts the delaying time based on the magnitude of load variation: when load variation is large (indicating actual occupant state change), the delaying time is reduced or eliminated, allowing immediate state switching; when load variation is small (indicating temporary posture change), the delaying time is extended to prevent frequent switching. This dynamic adjustment resolves the contradiction between stability and response speed.
Solution Approach 2:
The patent changes the parameter of delaying time based on the degree of load variation. By setting different delaying times corresponding to different load variation thresholds, the system adapts its response characteristics to the actual situation. This parameter change allows the system to maintain stability under normal conditions while responding quickly to actual occupant state changes.
2Reliability
If a fixed delaying time is applied to switch occupant determination state, then frequent switching due to temporary load variation is prevented, but the accuracy of immediate occupant state detection is reduced
Solution Approach 1:
The system dynamically adjusts the delaying time based on the magnitude of load variation. When the load variation exceeds a threshold (indicating actual occupant state change), the delaying time is reduced, allowing immediate and accurate detection of the new state. When load variation is within the threshold (indicating temporary posture change), the delaying time is extended to maintain reliability. This dynamic approach resolves the contradiction between reliability and measurement precision.
Solution Approach 2:
The patent changes the delaying time parameter according to the load variation magnitude. By setting multiple delaying time values corresponding to different load variation levels, the system achieves both high reliability (by filtering out temporary variations) and high measurement precision (by quickly responding to actual state changes).
3Measurement precision
If multiple determination thresholds with different delaying times are set, then the accuracy of adult occupant determination is improved, but the device complexity increases
Solution Approach 1:
The patent segments the determination process by dividing it into multiple threshold levels (first determination threshold and second determination threshold). Each threshold has its own delaying time setting. This segmentation allows the system to handle different occupancy scenarios with appropriate precision while keeping each individual threshold comparison simple, thus improving overall measurement precision without excessive complexity.
Solution Approach 2:
The patent implements a multi-threshold system that provides more determination levels than a single threshold would. This partial excessive action (using more thresholds than the minimum one) improves precision for distinguishing adult occupants from children or empty seats, while the complexity increase is managed by using simple comparison logic for each threshold level.
Data Source
AI summary
An occupant determining device includes a load detecting sensor provided on a seat body and a controller. The controller calculates a detected load value based on an output value of the load detecting sensor and performs occupant determination based on the detected load value. The occupant determination state is switched to an adult determination state when a certain delaying time elapses after the detected load value exceeds a determination threshold. The controller sets plural determination thresholds, and the larger each determination threshold being exceeded by the detected load value is, the shorter the delaying time is set.