Vehicle Rollover Detection Using Acceleration Sensor Zero Point Feedback
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Solution Overview
Problem
Existing vehicle rollover detection systems face challenges in accurately differentiating slow rollovers from non-rollover events, leading to false-positive interventions by assistance functions due to sensor offset compensation and zero point feedback, especially in cases where the roll angle is large but the acceleration signal is small.
Innovation Solution
A method and control unit that utilize acceleration sensors with zero point feedback to compare sensor signals and feedback signals against specific threshold values, ensuring reliable rollover detection by differentiating between large and small roll angles, and providing a rollover signal for timely activation of assistance functions, such as emergency calls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If zero point feedback is applied to compensate sensor offset, then measurement precision is improved for small roll angles, but reliability deteriorates for large roll angles where the useful signal becomes small
Solution Approach 1:
The detection range is segmented into two zones: a first detection range for small roll angles using zero point feedback, and a second detection range for large roll angles using raw sensor signals. This segmentation allows each zone to use the most appropriate detection method, resolving the contradiction between precision for small angles and reliability for large angles.
Solution Approach 2:
The system dynamically changes the detection parameter based on the current operating state. When the vehicle is in a stable state, zero point feedback is applied for precise small-angle detection. When a rollover is detected (large angle), the system switches to using raw sensor signals, changing the detection parameter to maintain reliability across the full range of motion.
2Ease of operation
If offset control is applied to maintain sensor zero position, then ease of operation is improved, but false-positive interventions increase due to reduced useful signal
Solution Approach 1:
The system dynamically adjusts the detection strategy based on the current roll angle. For small angles where offset control is active, the system uses appropriate thresholding. For large angles where offset control reduces the useful signal, the system switches to a different detection mode that avoids false positives, making the overall system adaptable rather than static.
Solution Approach 2:
The detection parameters (thresholds, signal processing methods) are changed based on the operating condition. When offset control is active and the useful signal is small, the system changes to a detection mode that is less sensitive to offset variations, thereby reducing false-positive interventions while maintaining ease of operation.
3Device complexity
If single threshold comparison is used for rollover detection, then device complexity is reduced, but measurement precision deteriorates in distinguishing slow rollovers
Solution Approach 1:
The detection algorithm is segmented into multiple comparison stages: first comparing against a first threshold value for rapid rollover detection, and second comparing against a second threshold value for slow rollover detection. This segmented approach improves precision for slow rollovers while keeping each individual comparison simple.
Solution Approach 2:
The system performs partial comparisons - using a first threshold for quick detection and a second threshold for confirmation in slow rollover cases. This partial multi-threshold approach provides the precision needed for slow rollovers without implementing a fully complex multi-stage algorithm for all cases.
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 enables reliable and precise recognition of slow rollovers, reducing false-positive interventions and ensuring timely assistance measures, even when sensor signals are small due to offset control, thereby enhancing the robustness of rollover detection systems.
Implementation Method 1
an acceleration sensor with zero point feedback... the sensor signal representing acceleration values detected by the at least one acceleration sensor
Data Source
AI summary
A method for controlling at least one assistance function in the event of a rollover of a vehicle. The vehicle includes at least one acceleration sensor with zero point feedback. The method includes reading in a sensor signal and ascertain or reading a feedback signal. The sensor signal represents acceleration values detected by the at least one acceleration sensor. The feedback signal represents control values for the zero point feedback of the at least one acceleration sensor. The method also includes determining an occurrence of a rollover as a function of a result of comparisons. Furthermore, the method includes providing a rollover signal for output to the at least one assistance function. The rollover signal represents a recognized rollover of the vehicle.