Dynamic Chassis Level Detection Filter Switching
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Solution Overview
Problem
Existing methods for detecting a motor vehicle's chassis level on a roadway often result in a high number of false alarms, particularly when the vehicle is starting off, due to low-pass filtering with a higher cut-off frequency that incorrectly identifies pitching as a dangerous situation.
Innovation Solution
A method that detects chassis level values and an operating variable indicating starting, determines the probability of a stationary or driving situation, and generates a driving chassis level characteristic value to suppress short-term level changes, avoiding unnecessary alarm messages by switching between persistence and drive filter modes based on the vehicle's state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If low-pass filtering with higher cut-off frequency is used to detect chassis level, then detection sensitivity is improved, but false alarm rate increases due to pitching during starting
Solution Approach 1:
The patent applies dynamics by making the filter cut-off frequency variable rather than fixed. The system dynamically adjusts the cut-off frequency based on vehicle operating conditions: using higher cut-off frequency (0.1 Hz) when vehicle speed is zero for sensitive detection, and lower cut-off frequency (0.001 Hz) when vehicle speed exceeds threshold to suppress pitching-induced false alarms. This dynamic adaptation resolves the contradiction between detection sensitivity and false alarm rate.
Solution Approach 2:
The patent changes the parameter of filter cut-off frequency based on vehicle speed condition. When vehicle speed is below threshold, the system uses first filter parameters (higher cut-off frequency) for sensitive detection. When vehicle speed exceeds threshold, it switches to second filter parameters (lower cut-off frequency) to eliminate false alarms from pitching. This parameter change strategy directly addresses the technical contradiction.
2Measurement precision
If low-pass filtering is applied during starting to detect chassis level, then detection accuracy is improved, but driver irritation increases due to superfluous warning signals
Solution Approach 1:
The system dynamically adapts the filtering strategy based on vehicle speed. During starting phase when vehicle speed is zero, high cut-off frequency filtering provides accurate detection. When vehicle speed exceeds threshold indicating pitching motion, the system switches to low cut-off frequency filtering to suppress false warnings, thereby eliminating driver irritation while maintaining detection accuracy when needed.
Solution Approach 2:
The patent changes filter parameters based on vehicle operating state. By monitoring vehicle speed and comparing with threshold, the system selects appropriate filter parameters: first parameters for stationary detection accuracy, second parameters for suppressing false alarms during motion. This parameter adaptation eliminates superfluous warnings that cause driver irritation.
3Ease of operation
If chassis level regulation is activated based on detected values, then chassis level control is improved, but unnecessary adjustments occur during starting
Solution Approach 1:
The patent applies dynamics by making the control activation condition variable. The system uses vehicle speed as a dynamic criterion: when speed is zero and chassis level is out of range, regulation is activated for accurate control. When speed exceeds threshold, regulation is suppressed to prevent unnecessary adjustments during pitching. This dynamic control strategy improves both ease of operation and reliability.
Solution Approach 2:
The patent changes the control activation parameter based on vehicle speed. By introducing speed threshold as a control parameter, the system enables chassis level regulation only when appropriate (stationary conditions). This parameter change prevents unnecessary adjustments during starting while maintaining effective control when vehicle is stationary.
Data Source
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AI summary
The method involves determining whether a persistence situation i.e. driving situation, exists with a preset probability from a driving speed (v) and starting-indicating operating variable, where a motor vehicle (10) is stopped in the persistence situation and no starting is directly impended. A driving chassis level characteristic value is produced from a chassis level value (C) if no persistence situation exists. A warning signal is outputted when the driving chassis level characteristic value lies outside a driving chassis level interval. An independent claim is also included for a data carrier with stored program for executing a method for detecting a level of a chassis of a motor vehicle.