Vehicle Speed Warning Hysteresis to Prevent Alert Chatter
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Solution Overview
Problem
Existing vehicle speed warning systems cause driver discomfort due to frequent ON/OFF transitions of warnings when vehicle speed fluctuates near the speed limit, leading to unnecessary alerts.
Innovation Solution
A warning device with a speed detection unit and a determination unit that sets a first threshold higher than the speed limit to initiate warnings and a second threshold lower than the first to stop warnings, providing a hysteresis characteristic to reduce frequent transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single speed threshold is used to determine warning activation, then the warning system is simple to operate, but frequent ON/OFF transitions occur when vehicle speed fluctuates near the threshold causing driver discomfort
Solution Approach 1:
The patent applies dynamics by transitioning from a static single threshold to a dynamic two-threshold system. The first threshold (higher) activates warnings, while the second threshold (lower) deactivates them. This dynamic approach adapts the warning system's behavior based on the direction of speed change, preventing frequent transitions when speed fluctuates near a single threshold value.
Solution Approach 2:
The patent changes the parameter of threshold values from a single value to two distinct values. By setting the first threshold higher than the second threshold, the system creates a hysteresis effect where the warning state depends on both the current speed and the previous state, thereby reducing unnecessary ON/OFF transitions and driver discomfort.
2Reliability
If the warning threshold is set close to the speed limit to provide timely warnings, then warning responsiveness is improved, but unnecessary warnings increase when speed fluctuates causing driver discomfort
Solution Approach 1:
The system dynamically adjusts the effective threshold based on the current warning state. When the warning is active, the threshold for deactivation (second threshold) is lower than the activation threshold (first threshold). This dynamic threshold adjustment ensures timely warnings while filtering out fluctuations that would cause unnecessary warning transitions.
Solution Approach 2:
The patent changes the parameter settings by establishing two distinct threshold values instead of one. The first threshold is set to activate warnings when speed exceeds it, while the second threshold is set lower to deactivate warnings. This parameter change creates a buffer zone that prevents unnecessary warnings during speed fluctuations near the speed limit.
Data Source
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AI summary
A warning device includes a speed detection unit (12) that detects a speed of a vehicle (1), and a determination unit (25) that determines to perform warning when the speed is higher than a first threshold and determines not to perform the warning when the speed is lower than a second threshold that is lower than the first threshold.