Vehicle Occupant Classification Using Lateral Acceleration Difference Thresholds
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Solution Overview
Problem
Existing occupant determination systems in vehicles face errors due to offset and sensitivity issues in acceleration sensors, leading to incorrect classification of occupants as adults or children during vehicle cornering, which affects the accuracy of airbag activation.
Innovation Solution
An occupant determination apparatus that uses a weight sensor, lateral acceleration sensor, and processing unit to calculate lateral acceleration differences and threshold values, determining whether to perform occupant classification based on these values to minimize errors caused by sensor inaccuracies, and maintaining previous determinations when significant acceleration differences are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If occupant determination is performed using acceleration sensor during vehicle cornering, then occupant classification can be continuously updated, but measurement precision deteriorates due to sensor errors and weight shift
Solution Approach 1:
The system preemptively identifies high lateral acceleration conditions and suspends occupant determination before erroneous classification can occur. By detecting when lateral acceleration exceeds the threshold, the system prevents incorrect occupant classification that would result from weight shift during cornering, rather than attempting to correct errors after they occur.
Solution Approach 2:
The system uses a simple lateral acceleration threshold comparison to determine when to suspend occupant classification, rather than employing complex error correction algorithms. This approach sacrifices continuous determination capability in favor of using a simple, reliable threshold-based mechanism to prevent measurement errors.
2Measurement precision
If occupant determination is suspended during high lateral acceleration to prevent errors, then measurement precision is maintained, but productivity decreases due to determination delays
Solution Approach 1:
The system pre-estimates the lateral acceleration difference threshold based on vehicle characteristics before actual cornering occurs. This preliminary setup allows the system to quickly compare current lateral acceleration against predetermined thresholds during cornering, enabling rapid resumption of occupant determination once conditions normalize, without requiring complex real-time calculations.
Solution Approach 2:
The system dynamically adjusts the suspension state based on real-time lateral acceleration conditions. When lateral acceleration exceeds the threshold, occupant determination is suspended; when it falls below, determination automatically resumes. This dynamic switching optimizes both precision and responsiveness by adapting the determination frequency to actual vehicle operating conditions.
3Reliability
If lateral acceleration difference threshold is set low to detect sensor errors, then reliability improves, but device complexity increases due to additional threshold management
Solution Approach 1:
The lateral acceleration difference threshold serves multiple functions: it detects sensor errors, identifies cornering conditions, and triggers suspension of occupant determination. By using a single threshold parameter for multiple purposes, the system achieves reliable error detection without requiring separate thresholds for each function, thereby limiting the increase in device complexity.
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 approach enhances the accuracy of occupant classification by accounting for sensor errors and maintaining previous determinations during high lateral acceleration, thereby reducing incorrect airbag deployments and improving safety.
Implementation Method 1
a weight sensor that senses a weight of an object on a seat of a vehicle
Implementation Method 2
a lateral acceleration sensor that senses lateral acceleration, which is acceleration in a width direction of the vehicle
Data Source
AI summary
An occupant determination apparatus includes a weight sensor that senses a weight of an object on a seat of a vehicle, a lateral acceleration sensor that senses lateral acceleration of the vehicle, and a processing unit that performs an operation of occupant determination. The processing unit calculates a lateral acceleration difference that is an absolute value of a difference between first lateral acceleration at a time when the weight passes through a first load threshold value and second lateral acceleration at a time when the weight passes through a second load threshold value. The processing unit performs the occupant determination based on an occupant determination threshold value when the lateral acceleration difference is smaller than a lateral acceleration difference threshold value, and does not perform the occupant determination when the lateral acceleration difference is larger than the lateral acceleration difference threshold value.