Vehicle Occupant Protection Device Offset Collision Thresholds
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Solution Overview
Problem
Existing vehicle occupant protection devices face challenges in accurately predicting and mitigating the rotational hazards during offset collisions, particularly in small overlap collisions, due to difficulties in detecting the rotation direction and speed of the vehicle body.
Innovation Solution
A vehicle occupant protection device that includes a front-rear impact magnitude detector, a right-left impact magnitude detector, an offset level detector, and a protection controller that selects appropriate lateral thresholds based on the overlap ratio, relative speed, and collision angle to operate airbags such as curtain airbags and windshield post airbags to provide enhanced protection during offset collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single fixed threshold is used for airbag operation, then the device complexity is reduced, but the protection reliability deteriorates in offset collisions due to inability to accurately predict rotation direction and speed
Solution Approach 1:
The patent applies dynamics by making the airbag operation threshold variable rather than fixed. The protection controller dynamically selects from multiple lateral thresholds based on detected collision parameters (overlap ratio, relative speed, collision angle) to accurately predict vehicle rotation and determine appropriate airbag deployment timing, thereby improving protection reliability without requiring overly complex real-time calculation systems
Solution Approach 2:
The patent changes the parameter of the operation threshold from a single fixed value to multiple variable thresholds selected based on collision conditions. By storing plural lateral thresholds and selecting appropriate ones according to detected overlap ratio, relative speed, and collision angle, the system adapts to different offset collision scenarios, improving reliability while maintaining manageable device complexity through pre-stored threshold values
2Measurement precision
If multiple lateral thresholds are stored and selected based on offset collision level, then the protection precision is improved, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-storing multiple lateral thresholds in the right-left threshold storage before collision occurs. The offset level detector pre-calculates collision parameters (overlap ratio, relative speed, collision angle) and selects the appropriate threshold in advance, enabling precise rotation detection without requiring complex real-time threshold calculation during the actual collision event
Solution Approach 2:
The system dynamically selects from multiple pre-stored lateral thresholds based on detected collision parameters. This dynamic selection process improves rotation detection precision by matching the threshold to the specific collision scenario, while the use of pre-stored values rather than real-time calculations keeps the device complexity at a manageable level
3Reliability
If airbags are operated based on predetermined fixed thresholds, then the response time is reduced, but the protection effectiveness deteriorates in offset collisions due to inaccurate rotation prediction
Solution Approach 1:
The patent applies preliminary action by pre-storing multiple lateral thresholds and pre-calculating collision parameters (overlap ratio, relative speed, collision angle) before the collision fully develops. This allows the protection controller to quickly select the appropriate threshold and deploy airbags at the optimal moment, maintaining fast response time while improving protection effectiveness through accurate rotation prediction specific to offset collision conditions
Data Source
AI summary
An airbag controller in a vehicle occupant protection device deploys airbags when one of a front-right acceleration sensor and a front-left acceleration sensor disposed on a front face of a vehicle detects an over-threshold acceleration exceeding a front threshold and one of a side-right acceleration sensor or a side-left acceleration sensor, which are disposed on a side face of the vehicle, detects an over-threshold acceleration exceeding a lateral threshold. A threshold acceleration storage device stores the front threshold and plural lateral thresholds that have respectively different values. An image processor processes image data from an in-vehicle camera and calculates the offset rate, an offset direction, a collision angle, a collision direction, and a relative speed at a timing just-before an offset collision between a subject vehicle and another vehicle. Based on a detection result, the airbag controller selects one of the plural lateral thresholds stored in the storage device.