Steering Control Device with Reaction Force Suppression for Lane Departure

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Solution Overview

Problem

Long-term reliance on drive assist systems can lead to reduced driver attention and increased risk of lane departure, as drivers become accustomed to the assistance and may not maintain adequate focus on driving.

Innovation Solution

A steering control device that adjusts the steering reaction force based on the lateral position relative to the white line, incorporating a reaction force suppression processing mechanism to reduce the steering reaction force when the vehicle is near the white line for an extended period, while maintaining the turning amount at the starting value, thereby reducing driver reliance on assist systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the steering reaction force increases as the vehicle moves away from the white line to suppress lane departure, then lane departure suppression is improved, but driver attention decreases due to excessive reliance on drive assist

Engineering Contradiction:
Improvelane departure suppressionVSAvoiddriver attention
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system periodically interrupts the drive assist function by reducing the steering reaction force when the vehicle remains in the same lane for a predetermined time, creating a periodic cycle of assist provision and interruption that prevents driver complacency while maintaining lane discipline

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The steering reaction force is dynamically adjusted based on the duration of lane maintenance, transitioning from a constant assist force to a variable force that decreases over time, thereby adapting the level of assistance to prevent excessive driver reliance

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the steering reaction force is reduced to increase driver attention, then driver attention is improved, but lane departure suppression deteriorates

Engineering Contradiction:
Improvedriver attentionVSAvoidlane departure suppression
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The steering reaction force reduction is applied locally in time and condition - only when the vehicle has maintained the same lane for a predetermined duration - rather than uniformly, allowing lane departure suppression to remain effective when needed while increasing driver attention when the vehicle is stable

Inventive Principle:
Principle #3Local quality

3Reliability

If the steering reaction force control amount is maintained at a high threshold value to suppress lane departure, then lane departure suppression is improved, but driver attention reduces due to continuous drive assist

Engineering Contradiction:
Improvelane departure suppressionVSAvoiddriver attention
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system implements periodic interruption of the high threshold steering reaction force by reducing it after a predetermined time period, creating cycles of assist provision and reduction that maintain lane departure suppression effectiveness while preventing driver over-reliance on the system

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3015343B1Steering control device
Publication Date: 2018.04.18 NISSAN MOTOR CO LTD
  • EP3015343B1 patent drawingFigure 1
  • EP3015343B1 patent drawingFigure 2
  • EP3015343B1 patent drawingFigure 3

AI summary

When a steering reaction force actuator for imparting steering reaction force to a steering unit is controlled based on a steering reaction force control amount in which the steering reaction force increases in the direction in which the lateral position of a host vehicle moves away from a white line in commensurate proximity to the white line, and when a turning actuator for imparting turning torque to a turning part mechanically separated from the steering unit is controlled based on a turning control amount in which the turning amount increases in the direction in which the lateral position of a host vehicle moves away from the white line in commensurate proximity to the white line, the steering reaction force control amount of reaction force suppression processing for reducing the steering reaction force control amount is computed when a state in which the steering reaction force control amount has been at a predetermined threshold value or higher for a predetermined length of time, and the reaction force suppression processing is carried out for controlling the steering reaction force actuator based on the steering reaction force control amount of reaction force suppression processing in lieu of the steering reaction force control amount, and meanwhile, the turning amount is maintained at the value occurring at the starting time point of the reaction force suppression processing when the reaction force suppression processing has started.