Driver State Assessment Using Residual Error

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional driver state assessment methods are ambiguous and delayed in assessing a driver's low wakefulness state, as they rely on control results from driving performance, lacking clear assessment indices.

Innovation Solution

A driver state assessment device that calculates a residual error based on the difference between actual and driver model operations, using a normalized residual error to assess the driver's state, with a first-order differential expression for driver model identification and frequency filtering to enhance precision and stability assessment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If driver state assessment is based on control results from driving performance (azimuth deviation), then the assessment can be performed using available sensor data, but the assessment is delayed because it waits for changes in vehicle behavior

Engineering Contradiction:
Improveassessment delayVSAvoidassessment precision
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by using a driver model to predict the driver's intended steering operations before the driver actually executes them. The system identifies a driver model from historical data, then uses this model to generate predicted steering angles in advance. By comparing these predicted angles with actual steering inputs, the system can detect deviations that indicate drowsiness before they manifest in vehicle behavior changes, thus eliminating the time delay while maintaining assessment precision.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If Bode plot comparison is used to evaluate driver model characteristics, then the driver model can be compared with a standard driver model, but the assessment criteria become ambiguous and unclear

Engineering Contradiction:
Improveassessment precisionVSAvoidassessment clarity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent applies parameter changes by transforming the complex Bode plot comparison into a simpler residual error metric. Instead of comparing entire frequency response curves and interpreting ambiguous shape characteristics (peak vs flat), the system calculates a single residual error value representing the difference between predicted and actual steering angles. This quantitative parameter provides clear, unambiguous assessment criteria while maintaining the ability to detect driver state changes with high precision.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If driver model identification is performed using azimuth deviation and steering angle data, then the driver's input/output relationship can be captured, but the system complexity increases

Engineering Contradiction:
Improvedriver model accuracyVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by implementing a recursive identification process where the driver model automatically updates itself using ongoing driver behavior data. The system continuously refines the driver model parameters without requiring external recalibration or complex manual adjustments. This self-updating mechanism maintains high driver model accuracy and adaptability while minimizing the operational complexity for users, as the system performs the complex identification tasks autonomously.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS8489253B2Driver state assessment device
Publication Date: 2013.07.16 HONDA MOTOR CO LTD
  • US8489253B2 patent drawing
  • US8489253B2 patent drawing
  • US8489253B2 patent drawing

AI summary

A driver state assessment device is provided in which when driver model identification means (M2) identifies a driver model showing a driver's input/output relationship using a difference between a target azimuth and an actual azimuth as a driver's input and an actual steering angle as a driver's output, driver model amount of operation acquisition means (M3) acquires a driver model steering angle by inputting a current azimuth deviation into the driver model, and driver state assessment means (M4) calculates a difference between a current actual steering angle and a driver model steering angle as a residual error and assesses the driver's state based on the residual error. Therefore, since the residual error is an index that represents a fluctuation component, a noise component, a non-linear component, etc. obtained from the driver model, it is possible to assess, with high precision, the driver's state, in particular a low wakefulness state of the driver, based on this residual error.