Multi-Axis Crash Acceleration Sensing and Safing Threshold Control
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Solution Overview
Problem
Existing vehicle crash detection systems face challenges in accurately determining crash conditions and controlling actuatable safety devices, particularly in discriminating between deployment and non-deployment events, due to limitations in sensing multiple axes of acceleration and filtering out extraneous signals.
Innovation Solution
A method and apparatus that utilize a combination of accelerometers to sense crash acceleration in multiple directions, including a first direction parallel to the front-to-rear axis and a second direction parallel to the side-to-side axis, with a controller determining a transverse crash value and comparing it against a safing threshold to accurately assess vehicle crash conditions and control actuatable occupant restraint systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple accelerometers are used to sense crash acceleration in multiple directions, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system divides the crash detection function into multiple specialized accelerometers positioned at different locations (front, side, rear) and orientations (longitudinal, transverse). Each accelerometer segment measures specific crash components, and the controller integrates these segmented measurements to achieve comprehensive crash condition determination with high precision while managing complexity through functional division.
2Reliability
If transverse crash value comparison against safing threshold is implemented, then reliability of safety device actuation is improved, but false activations may occur due to extraneous signals
Solution Approach 1:
The controller continuously monitors accelerometer signals and compares transverse crash values against predetermined safing thresholds. When signals exceed thresholds, the system provides feedback through additional signal filtering and validation logic that distinguishes between genuine crash conditions and extraneous signals (such as road bumps or door slams), thereby improving reliability while preventing false activations.
Solution Approach 2:
The system dynamically adjusts the interpretation of accelerometer signals by changing parameters such as threshold values and signal filtering characteristics based on the specific crash scenario detected. By modifying these parameters in response to different signal patterns, the system maintains high reliability in determining when to activate safety devices while filtering out extraneous signals that do not represent actual crash conditions.
3Measurement precision
If side satellite accelerometers are used to determine transverse crash metric, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The side satellite accelerometers are designed to perform multiple functions: they measure transverse crash metrics for side impact detection, provide longitudinal acceleration data for forward/rearward crash assessment, and contribute to overall vehicle dynamics monitoring. This multi-functionality improves measurement precision across different crash scenarios while reducing device complexity by eliminating the need for separate dedicated sensors for each measurement type.
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 crash condition determination and actuation of safety devices by filtering out non-deployment events, ensuring proper deployment in actual crash scenarios while preventing false activations, thereby improving occupant safety.
Implementation Method 1
a first accelerometer for sensing crash acceleration in a first direction substantially parallel to a front-to-rear axis of the vehicle and providing a first acceleration signal indicative thereof
Implementation Method 2
second accelerometers for sensing crash acceleration in a second direction substantially parallel to a side-to-side axis of the vehicle and near opposite sides of the vehicle and providing second acceleration signals indicative thereof
Data Source
AI summary
A method for determining a crash condition of a vehicle comprises the step of sensing crash acceleration in a first direction substantially parallel to a front-to-rear axis of the vehicle and providing a first acceleration signal indicative thereof. The method also comprises the step of sensing crash acceleration in a second direction substantially parallel to a side-to-side axis of the vehicle and near opposite sides of the vehicle and providing second acceleration signals indicative thereof. The method further comprises the steps of determining a transverse crash value functionally related to the second acceleration signals and comparing the determined transverse crash value against a safing threshold. The method still further comprises the step of determining a crash condition of the vehicle in response to (a) the comparison and (b) the first acceleration signal.