Steering Wheel Signal Analysis for Drowsiness Detection

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Solution Overview

Problem

Current drowsiness detection systems for drivers face challenges such as the impracticality of EEG measurements, the expense and difficulty of unobtrusive eye closure monitoring, and the limitations of vehicle state variable methods due to environmental dependencies and variability between vehicle types, leading to inaccurate and uncomfortable detection methods.

Innovation Solution

A drowsiness detection system utilizing Empirical Mode Decomposition (EMD) of steering wheel signals to extract features indicative of driver drowsiness, independent of road geometry and adaptable to individual driving styles, which classifies drivers as alert or drowsy based on steering control degradation phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If EEG measurements are used to detect driver drowsiness, then detection accuracy is improved, but the system becomes impractical due to the need for electrodes attached to the scalp

Engineering Contradiction:
Improvedetection accuracyVSAvoidpracticality
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent extracts the useful information (steering control patterns indicative of drowsiness) from the steering wheel system itself, eliminating the need for direct physiological measurements like EEG that require intrusive electrodes. By focusing on the steering wheel angle, velocity, and acceleration data, the system achieves practical implementation while maintaining detection capability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If unobtrusive eye closure monitoring is used to detect driver drowsiness, then driver comfort is improved, but the system becomes expensive and difficult to implement under certain conditions

Engineering Contradiction:
Improvedriver comfortVSAvoidimplementation difficulty
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent uses the steering wheel as an intermediary device to indirectly measure driver drowsiness. Instead of directly monitoring the driver's eyes or physiological state, the system measures steering wheel parameters (angle, velocity, acceleration) that change characteristically when a driver becomes drowsy, providing an indirect but effective measurement method.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If vehicle state variable methods are used to detect driver drowsiness, then non-intrusive detection is achieved, but accuracy is reduced due to environmental dependencies and variability between vehicle types

Engineering Contradiction:
Improvenon-intrusive detectionVSAvoiddetection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies dynamic analysis by examining the temporal patterns and rates of change in steering wheel parameters rather than static values. By analyzing steering wheel velocity and acceleration along with angle data, the system captures the dynamic characteristics of steering behavior that change when a driver becomes drowsy, improving accuracy while maintaining non-intrusive detection.

Inventive Principle:
Principle #15Dynamics

4Ease of operation

If steering wheel angle data is used to detect driver drowsiness, then unobtrusive detection is achieved, but the system fails to account for road curvature and vehicle speed variations

Engineering Contradiction:
Improveunobtrusive detectionVSAvoidenvironmental adaptability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent goes beyond using only steering wheel angle data by incorporating additional parameters (velocity and acceleration) and environmental context (road curvature, vehicle speed). This excessive action of collecting more data than the minimum required allows the system to differentiate between steering changes caused by drowsiness versus those caused by environmental factors, improving environmental adaptability.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS8519853B2Unobtrusive driver drowsiness detection system and method
Publication Date: 2013.08.27 GEORGE WASHINGTON UNIVERSITY
  • US8519853B2 patent drawing
  • US8519853B2 patent drawing
  • US8519853B2 patent drawing

AI summary

A drowsiness detection system and method uses Empirical Mode Decomposition (EMD) signal processing to detect whether a vehicle driver is drowsy. The system uses a decomposed component of the steering wheel signal to extract specific features representing the steering control degradation phases. The system classifies the measured features into alert or drowsy state. The detection system is independent of the road geometry and automatically compensates steering control performance variability between drivers. The system is accurate in detecting the drowsy periods and drowsy-related lane departures. The detection system is unobtrusive and can be applied on-line.