Driver Seat Awakening System Using Pulse Wave Analysis
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Solution Overview
Problem
Current driver monitoring systems struggle to accurately detect the transition from an active state to a sleep state in real-time, particularly while driving, and lack effective means to awaken drivers who may not respond to traditional alarm sounds, relying solely on Lyapunov exponent analysis and heart rate or pulse measurements.
Innovation Solution
A driver seat system with a bio-signal measurement instrument and analyzer that includes mechanisms for detecting bio-signal peak values, calculating power values, and analyzing gradients of both power values and Lyapunov exponents to determine predictive signals for sleep onset, combined with a reclining mechanism to stimulate the driver's pressure sense and prevent falling asleep.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If brain wave measurement is conducted to detect driver condition, then measurement precision is improved, but device complexity increases due to requiring electrodes on the head
Solution Approach 1:
The patent extracts the measurement function from the head (brain wave electrodes) to the hand (finger pulse), eliminating the need for complex head electrode placement while maintaining driver condition detection capability through pulse wave analysis
Solution Approach 2:
The patent uses pulse wave as an intermediary indicator to indirectly assess driver condition (alertness/fatigue state) without directly measuring brain waves, simplifying the measurement system while preserving diagnostic value
2Reliability
If only alarm sound is used to awaken the driver, then device complexity is reduced, but reliability of awakening decreases for drivers with weak response
Solution Approach 1:
The patent implements a dynamic awakening system that adapts to individual driver responses, using multiple stages (alarm sound → seat vibration → seat heating) that can be activated sequentially based on the driver's reaction to ensure reliable awakening
Solution Approach 2:
The patent combines multiple awakening mechanisms (acoustic alarm, mechanical vibration, thermal heating) into a composite awakening system, leveraging different sensory modalities to ensure effective driver activation even when one method fails
3Measurement precision
If only Lyapunov exponent analysis is used to detect sleep state, then device complexity is reduced, but measurement precision decreases for real-time detection
Solution Approach 1:
The patent segments the pulse wave signal analysis into multiple independent indicators (Lyapunov exponent for chaos analysis, power values for energy metabolism, gradient calculations for rate of change), allowing comprehensive sleep state detection through combination of simpler analyses
Solution Approach 2:
The patent makes the pulse wave measurement system multi-functional by extracting multiple parameters (Lyapunov exponent, power values, gradients) from the same signal source, enabling both sleep detection and energy metabolism monitoring without additional sensors
Data Source
AI summary
There are provided a monitor for monitoring a human condition of a driver, and an awakening device for awakening a driver, which starts operation when received a predictive signal for fall-asleep being a signal for energy metabolism transition from an active state into a sleep state. The awakening device is structured to stimulate a pressure sense of the driver by reclining a seat back of a driver seat forward or rearward to thereby cause a shift force. Accordingly, without regard to an alarm reaction level to an alarm sound, it is possible to stimulate the driver and whereby awaken the driver more surely.