Vehicle Rollover Detection Using Vertical Acceleration Counter
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Solution Overview
Problem
Existing rollover detection methods for motor vehicles, particularly those using yaw rate sensors, are costly and prone to errors due to sensitivity to absolute angle, inclined road conditions, and slow turns, while alternative acceleration-based methods lack cost-effectiveness and reliability.
Innovation Solution
A counter-based method utilizing an acceleration sensor in the vertical axis, where the counter increments within a predetermined acceleration range and decrements outside it, triggering an emergency call when a predetermined count is reached, with adaptations for vehicle-specific conditions and speed limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If yaw rate sensors are used for rollover detection, then angular momentum can be detected at an early stage, but the costs are not insignificant and the sensors are prone to errors due to sensitivity to absolute angle and inclined road conditions
Solution Approach 1:
The patent replaces expensive yaw rate sensors with a combination of inexpensive acceleration sensors and basic vehicle data (from existing systems). The acceleration sensor evaluates vertical axis acceleration over time with a counter mechanism that integrates acceleration values, providing a cost-effective alternative that achieves reliable rollover detection without the high costs and complexities of gyroscopic sensors
Solution Approach 2:
The patent substitutes the mechanical gyroscopic measurement system with an electronic integration approach using acceleration sensors. Instead of directly measuring angular momentum mechanically, the system integrates acceleration data over time and evaluates it against threshold criteria, replacing complex mechanical sensing with simpler electronic computation
2Device complexity
If acceleration sensors are used for rollover detection, then costs are reduced, but isolated measured value errors can affect evaluation reliability
Solution Approach 1:
The patent implements a counter that accumulates acceleration values over a predetermined time period before making a rollover determination. This preliminary integration of multiple acceleration measurements allows isolated erroneous values to be diluted by surrounding valid measurements, preventing single-point errors from triggering false alarms while maintaining cost-effective sensor usage
Solution Approach 2:
The system continuously monitors acceleration values and adjusts the counter accordingly, with the counter being increased or decreased based on whether acceleration exceeds threshold values. This feedback mechanism ensures that transient errors do not lead to incorrect rollover detection, as the counter requires sustained threshold exceedance rather than momentary spikes
3Device complexity
If a time-based evaluation method is used, then implementation is simple, but isolated measurement errors have significant influence on the overall evaluation
Solution Approach 1:
Instead of making immediate rollover decisions based on single time-point measurements, the patent accumulates acceleration values in a counter over a predetermined time period. This preliminary integration approach maintains simple implementation while significantly reducing error sensitivity, as isolated measurement errors represent only a small portion of the total accumulated value
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 provides a cost-effective and robust rollover detection system, minimizing the impact of isolated measurement errors and ensuring accurate emergency call triggering, particularly during low-speed events, thus enhancing occupant protection without relying on expensive yaw rate sensors.
Implementation Method 1
The acceleration in the direction of the vertical axis of the vehicle is evaluated and in particular the duration in which the acceleration is within a specified range is evaluated. The effect of gravity on the acceleration sensor in the vertical axis changes significantly when the vehicle is in a roof or extremely inclined position.
Data Source
AI summary
The invention relates to a method for detecting a rollover on the basis of a signal of an acceleration sensor in the direction of the vertical axis of the vehicle. For this purpose, a counter and a clock pulse generator are provided. The counter is increased each clock pulse if the acceleration lies within a specified range, and the counter is decreased maximally to the value of null if the acceleration lies outside of a specified range. An emergency call is preferably triggered if a specified counter state is reached. Additionally, a maximum speed is preferably specified in the travel direction above which the counter or the trigger is not active.