Dual-Axis Crash Detection for Vehicle Safety Systems
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Solution Overview
Problem
Current vehicle crash detection systems are inadequate in accurately determining crash conditions and controlling actuatable safety devices, as they rely on single-axis acceleration sensing, which can lead to false deployments or failures in discriminating between crash events and non-crash events like road noise or misuse.
Innovation Solution
A method and apparatus that utilize dual-axis accelerometers to sense crash acceleration in both front-to-rear and side-to-side directions, generating crash metric values to determine vehicle crash conditions by comparing these values against thresholds, and a controller that discriminates between deployment and non-deployment crash events using algorithms and filters to ensure accurate actuation of occupant restraint systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single-axis acceleration sensing is used, then device complexity is reduced, but measurement precision deteriorates leading to false deployments
Solution Approach 1:
The patent transitions from single-axis (one-dimensional) acceleration sensing to dual-axis (two-dimensional) acceleration sensing. By adding the side-to-side axis sensing capability, the system can differentiate between frontal crashes and lateral impacts, significantly improving measurement precision without excessive complexity increase.
Solution Approach 2:
The sensing function is segmented into two independent acceleration sensors, each dedicated to a specific axis (front-to-rear and side-to-side). This segmentation allows each sensor to specialize in detecting crashes in its respective direction, improving overall measurement precision while keeping individual sensor complexity low.
2Measurement precision
If dual-axis accelerometers are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the functions of two acceleration sensors and integrates them with the control unit into a unified crash detection system. The control unit processes signals from both axes simultaneously, combining the information to make deployment decisions, thereby managing complexity through functional integration rather than separate independent systems.
Solution Approach 2:
The control unit is designed with multi-functionality, handling not only processing of dual-axis acceleration data but also implementing crash algorithms, filtering signals, and controlling the deployment of multiple types of safety devices (frontal and side airbags). This universal approach reduces overall system complexity despite the increased sensing capability.
3Reliability
If crash metric comparison against threshold is implemented, then reliability is improved, but loss of time increases due to processing requirements
Solution Approach 1:
The system performs preliminary actions by continuously monitoring acceleration signals and pre-calculating crash metrics even before a crash event is fully detected. The control unit is pre-programmed with crash algorithms and threshold values, so when a crash occurs, the comparison and decision-making process can proceed rapidly without delay for setup or configuration.
Solution Approach 2:
The patent implements a streamlined crash detection algorithm that skips unnecessary processing steps. The control unit directly compares crash metrics against pre-established thresholds and immediately triggers deployment decisions when thresholds are exceeded, rushing through the critical decision-making phase to minimize time loss while maintaining reliability.
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 detection and actuation control, reducing false deployments and improving occupant safety by effectively distinguishing between crash events and non-crash events, thereby optimizing the deployment of actuatable safety devices.
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 crash acceleration signal indicative thereof
Implementation Method 2
a second accelerometer for sensing crash acceleration in a second direction substantially parallel to a side-to-side axis of the vehicle and providing a second crash acceleration signal indicative thereof
Data Source
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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 crash acceleration signal indicative thereof. The method also comprises ihe step of sensing crash acceleration in a second direction substantially parallel to a skie-to-side axis of the vehicle and providing a second crash acceleration signal indicative thereof. The method further comprises the steps of determining a crash metric value functionally related to the sensed crash acceleration based on the second acceleration signal and comparing the determined crash metric value as a function of the sensed first crash acceleration signal against an associated 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.