Adaptive Drowsiness Stimulus Control for Driver Safety
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Solution Overview
Problem
Existing wakefulness maintaining apparatuses for vehicles often fail to supply stimuli in a manner that avoids discomfort to drivers, leading to potential disturbance in driving operations, as they do not adequately account for subjective drowsiness levels and fluctuating attention during monotonous driving.
Innovation Solution
A wakefulness maintaining apparatus that includes an event detecting part, drowsiness level determining part, threshold setting part, level range determining part, and stimulus supplying part, which supplies an awakening stimulus only when the drowsiness level is in a higher range and an event related to drowsiness is detected, and adjusts the stimulus interval based on the trend of drowsiness levels, ensuring the stimulus is provided at times corresponding to the driver's subjective experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stimulus is supplied to the driver when the frequency counter exceeds the threshold frequency, then the driver's wakefulness is maintained, but the driver may feel uncomfortable or be surprised by the sudden stimulus
Solution Approach 1:
The system performs preliminary action by detecting drowsiness events and accumulating evidence before supplying the stimulus. The event detecting part continuously monitors for drowsiness indicators, and only triggers the stimulus after a predetermined number of events are detected, ensuring the stimulus is supplied at the appropriate moment when the driver actually needs it without causing unnecessary surprise
Solution Approach 2:
The system uses feedback by continuously monitoring the driver's state through the event detecting part and adjusting stimulus supply based on the accumulated drowsiness events. The frequency counter N and threshold frequency Ns create a feedback mechanism that adapts to the driver's actual drowsiness level, supplying stimuli only when the detected events indicate genuine drowsiness rather than normal driving variations
2Reliability
If the stimulus is supplied every fixed interval when drowsiness exceeds a threshold, then the wakefulness is maintained, but the stimulus may be supplied when the driver is already awake causing annoyance
Solution Approach 1:
The system applies dynamics by making the stimulus supply condition adaptive rather than fixed. Instead of supplying stimuli at regular intervals, the system dynamically adjusts stimulus supply based on the detected drowsiness events. The threshold frequency Ns and frequency counter N create a dynamic threshold that adapts to the driver's actual state, ensuring stimuli are supplied only when genuinely needed
Solution Approach 2:
The system changes parameters by using multiple threshold levels (first threshold frequency Ns1 and second threshold frequency Ns2) and adjusting the stimulus supply decision based on the accumulated frequency counter N. This parameter-based approach allows the system to differentiate between temporary drowsiness fluctuations and sustained drowsiness states, supplying stimuli only when the parameter thresholds indicate genuine need
3Measurement precision
If the drowsiness level is determined as an average over a predetermined time, then the measurement is stable, but the stimulus may be supplied when the driver's current wakefulness is actually high
Solution Approach 1:
The system uses periodic action by continuously detecting drowsiness events at regular intervals and accumulating them over time. Instead of relying on a single average measurement, the system performs periodic detections and supplies stimuli when the accumulated count reaches the threshold, ensuring both measurement stability and timely response to actual drowsiness
Solution Approach 2:
The system performs preliminary detection and accumulation of drowsiness events before making the stimulus supply decision. The event detecting part continuously monitors and accumulates evidence in the frequency counter N, preparing the data needed for accurate drowsiness assessment before the actual stimulus supply occurs, thus reducing delayed response
Data Source
AI summary
A wakefulness maintaining apparatus includes an event detecting part, a drowsiness level determining part, a threshold setting part, and a stimulus supplying part. The event detecting part detects an event related to a drowsiness of a person. The drowsiness level determining part determines a drowsiness level that changes in accordance with a strength of the drowsiness. The threshold setting part sets a threshold value to divide the drowsiness level into a first level range and a second level range in such a manner that the first level range is equal to or lower than the threshold value and the second level range is higher than the threshold value. The stimulus supplying part supplies a stimulus having an awaking effect to the person when the drowsiness level is in the second level range and the event is detected.