Steering Wheel Excitation Sensing for Early Driver State Detection

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Solution Overview

Problem

Existing driver state determination systems fail to accurately detect abnormal states early enough, as they rely on involuntary movement decline, leaving little time for intervention before the driver becomes unable to operate the vehicle safely.

Innovation Solution

A driver state determination apparatus that uses a vibration apparatus to apply a predetermined excitation frequency to the steering wheel, detecting changes in vibration strength and standard deviation to determine abnormal states before involuntary movement decline, utilizing a steering torque sensor and controller to assess muscle responsiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If driver state determination relies on detection of inability to perform operation (involuntary movement decline), then the determination is made when the driver becomes unable to drive, but there is little time left for intervention before the driver becomes unable to operate the vehicle safely

Engineering Contradiction:
Improvedetermination accuracyVSAvoidintervention time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary detection of driver abnormality by monitoring voluntary movement function (steering wheel vibration response) before the driver completely loses operational ability. The vibration detection apparatus applies vibration to the steering wheel and measures the driver's muscle response to detect abnormalities in voluntary movement, enabling early warning before the driver becomes unable to operate the vehicle safely.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the system waits for the driver to become completely unable to perform operation before determining abnormality, then the determination is clear and unambiguous, but the detection occurs too late for effective intervention

Engineering Contradiction:
Improveabnormal state determination reliabilityVSAvoidtime for confirmation and action
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary detection of driver abnormality by monitoring voluntary movement function (steering wheel vibration response) before the driver completely loses operational ability. The vibration detection apparatus applies vibration to the steering wheel and measures the driver's muscle response to detect abnormalities in voluntary movement, enabling early warning before the driver becomes unable to operate the vehicle safely.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of waiting for complete loss of operational ability (excessive threshold), the system detects partial degradation of voluntary movement function. By measuring changes in vibration response characteristics (amplitude, frequency, phase) that indicate muscle function decline, the system triggers warnings during the transitional phase when the driver still retains some operational capability but shows signs of deterioration.

Inventive Principle:
Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables early detection of physical function decline and determination of abnormal states, allowing for timely intervention to ensure vehicle safety by analyzing the average and standard deviation of steering torque levels during vibration, thereby preventing accidents.

Implementation Method 1

a vibration apparatus (14) that gives vibration to a steering wheel (2) of a steering apparatus (1a) of the vehicle

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP4286252A1Driver state determination apparatus
Publication Date: 2023.12.06 MAZDA MOTOR CORP
  • EP4286252A1 patent drawingFigure 1
  • EP4286252A1 patent drawingFigure 2
  • EP4286252A1 patent drawingFigure 3

AI summary

[Problem] A driver state determination apparatus capable of detecting the decline of the physical function of a driver and confirming the determination of an abnormal state early on in a stage that is sufficiently before the driver becomes unable to drive is provided. [Means for solution] A driver state determination apparatus 10 includes: a vibration apparatus 14 that gives vibration to a steering wheel 2; a vibration detector 16 that detects the vibration of the steering wheel; and a controller 18 that controls the vibration apparatus. The controller gives vibration at a predetermined excitation frequency f0 to the steering wheel by the vibration apparatus, calculates a steering torque level at the excitation frequency based on the vibration detected by the vibration detector, and determines that a driver is in an abnormal state when an average value A of the steering torque level while the vibration is being given is equal to or more than a first threshold value Th1 and/or a standard deviation SD of the steering torque level while the vibration is being given is equal to or more than a second threshold value Th2.