Lane Keeping Control Using Dashed Line Detection for Variable Width Lanes

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Solution Overview

Problem

Conventional vehicle travel support devices struggle to maintain the host vehicle at an appropriate position within its lane when lane widths increase, particularly at right turn lanes or exit lanes on local roads and freeways, due to shifting lane boundaries and mixed line types.

Innovation Solution

A travel control system that includes a boundary-line recognition unit and a travel control unit, utilizing a camera and radar to detect lane boundaries and adjust the vehicle's position based on dashed or solid lines, ensuring the vehicle stays within the lane by controlling the steering and braking systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the vehicle travel support device uses the solid line representing the boundary between the road and shoulder or centerline as a reference when lane width increases, then the device can maintain basic lane keeping function, but the vehicle will be guided toward the right side (for right turn lane) or left side (for exit lane), causing inability to control the host vehicle at an appropriate position within its lane

Engineering Contradiction:
Improvelane keeping functionVSAvoidvehicle position within lane
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system applies different reference line selection criteria to different road scenarios. When lane width increases are detected, the system specifically looks for dashed lines (indicating lane divisions) rather than solid lines (indicating road boundaries), allowing appropriate reference selection based on local road configuration and line type characteristics

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically switches reference line selection based on detected road conditions. When lane width expansion is detected, the system transitions from using solid boundary lines to using dashed lane division lines as references, adapting the control strategy to the specific traffic scenario

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the vehicle travel support device uses conventional lane mark recognition methods, then the device can operate on standard roads with consistent lane widths, but the device fails when lane width increases along the planned travel road due to shifting boundary lines

Engineering Contradiction:
Improveautomatic travel supportVSAvoidadaptability to lane width changes
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system performs preliminary detection of lane width changes by monitoring the positions of left and right lane marks. When an increase in lane width is detected before the vehicle reaches the expanded section, the system proactively switches reference line selection strategy, preparing for the upcoming lane configuration change

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the critical parameter for reference line selection from line position (distance from vehicle) to line type (dashed vs. solid). This parameter change allows the system to distinguish between road boundary lines and lane division lines, enabling proper adaptation to lane width expansions

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3483022B1Travel control method and travel control device
Publication Date: 2020.11.04 NISSAN MOTOR CO LTD
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AI summary

A travel control method of the present invention includes: recognizing the lane in which the host vehicle is traveling; controlling the travel of the host vehicle such that the host vehicle is situated at a predetermined position relative to a boundary line of the lane; detecting an increase in the lane width of the lane in which the host vehicle is traveling; and, if determining that one of the boundary lines situated to the left and the right of the host vehicle is a dashed line, controlling the travel of the host vehicle based on the dashed boundary line.