Curve Target Locus Control for Driver Comfort

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Solution Overview

Problem

Conventional driving support technologies fail to effectively set a target locus that reduces the uncomfortable feeling experienced by drivers when traveling along curves during automatic driving.

Innovation Solution

A driving support apparatus that detects a travel possible region and sets a target locus by determining a road center as a reference point ahead, with a pre-read distance based on vehicle speed, and a lateral displacement based on the curve's radius of curvature, allowing the vehicle to pass through its own position and a target point inside the curve, which is adjusted according to vehicle speed and curve shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the vehicle travels along the road center line during automatic driving on curves, then the driving support system maintains simple locus control, but the driver experiences uncomfortable feeling and unease

Engineering Contradiction:
Improvedriver comfortVSAvoidlocus control complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies local quality by making the target locus different from the road center line in specific situations (curves). The controller sets the target locus to pass through positions inside the curve rather than always following the road center, creating localized adjustments that improve driver comfort without overhauling the entire control system.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses preliminary action by calculating and setting the target locus in advance based on pre-read distance and curve characteristics. The controller determines the target point inside the curve before the vehicle reaches it, allowing smooth locus control adjustments rather than reactive corrections.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the target locus is set to pass through positions inside the curve, then driver comfort is improved, but the locus control system becomes more complex

Engineering Contradiction:
Improvedriver comfortVSAvoidcontroller complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the target locus parameters (position offset from road center) based on curve characteristics. The controller adjusts the lateral position of the target point inside the curve using calculations involving pre-read distance, radius of curvature, and lane width, rather than changing the fundamental control architecture.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the pre-read distance is increased for faster vehicle speeds, then the target locus becomes more accurate for high-speed curves, but the calculation complexity increases

Engineering Contradiction:
Improvetarget locus accuracyVSAvoidcalculation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the pre-read distance variable rather than fixed. The controller adjusts the pre-read distance based on vehicle speed, using longer distances for higher speeds and shorter distances for lower speeds. This dynamic adjustment optimizes target locus accuracy for different driving conditions without requiring overly complex calculations.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2991871B1Driving support apparatus and driving support method
Publication Date: 2017.06.28 TOYOTA JIDOSHA KK
  • EP2991871B1 patent drawingFigure 1
  • EP2991871B1 patent drawingFigure 2~3
  • EP2991871B1 patent drawingFigure 4~5

AI summary

A driving support apparatus includes a travel possible region detecting device configured to detect a travel possible region of a vehicle, a travel controller configured to carry out locus control based on a target locus created so as to cause the vehicle to travel in the travel possible region detected by the travel possible region detecting device, and a controller configured to decide a road center of a curve, which is located forward of a traveling direction from a driver's own vehicle position of the vehicle by a pre-read distance which is set according to a vehicle speed of vehicle, as a reference point, at the time the curve exists forward of the traveling direction of the vehicle, decide a position offset from the reference point to inside of the curve by a lateral displacement which is set according to a radius of curvature of the curve at the reference point, as a target point, and create the target locus so as to cause the target locus to pass through the driver's own vehicle position and the target point.