Vehicle Turning Control Stop Unit for Low Friction Stability

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Solution Overview

Problem

Conventional collision avoidance systems for vehicles often result in unstable vehicle behavior and uncomfortable driving experiences due to excessive steering on low-friction road surfaces, as they fail to adjust turning control in response to changing road conditions.

Innovation Solution

A driving support system that includes a recognition unit, a support control unit for turning control, and a turning control stop unit, which stops excessive turning control when the vehicle's state deviates from a predetermined normal range, allowing the system to adjust braking forces to maintain stability and comfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If turning control is applied to avoid collision on low-friction road surfaces, then collision avoidance capability is improved, but vehicle stability deteriorates due to excessive steering

Engineering Contradiction:
Improvecollision avoidance capabilityVSAvoidvehicle stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The control system dynamically adjusts the turning control based on detected road surface friction conditions. When low friction is detected, the system modifies the turning control parameters to prevent excessive steering, thereby maintaining vehicle stability while still achieving collision avoidance. This dynamic adaptation resolves the contradiction by making the control strategy flexible rather than fixed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes control parameters (such as steering angle commands, yaw rate targets) based on the detected road surface friction coefficient. By adjusting these parameters according to friction conditions, the system achieves both collision avoidance and stability maintenance, resolving the technical contradiction between these two opposing requirements.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If turning control is applied to achieve desired turning state, then collision avoidance is improved, but driver comfort deteriorates due to mismatched steering feeling

Engineering Contradiction:
Improvecollision avoidance capabilityVSAvoiddriver comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system adjusts steering control parameters based on road friction detection to match driver expectations. On low-friction surfaces, it modifies the steering response characteristics to prevent over-turning, thereby maintaining both collision avoidance effectiveness and driver comfort by aligning the vehicle's actual behavior with driver intent.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If automatic turning control is applied for collision avoidance, then safety is improved, but vehicle control stability deteriorates when road friction varies suddenly

Engineering Contradiction:
ImprovesafetyVSAvoidvehicle control stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The system continuously monitors road surface friction conditions and vehicle state parameters during turning control. When sudden friction changes are detected, the feedback mechanism triggers real-time adjustments to the turning control parameters, preventing instability and maintaining both safety and control stability despite varying road conditions.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2763121B1Driving support system for a vehicle
Publication Date: 2021.10.27 TOYOTA JIDOSHA KK
  • EP2763121B1 patent drawingFigure 1
  • EP2763121B1 patent drawingFigure 2
  • EP2763121B1 patent drawingFigure 3

AI summary

When a solid object is recognized in the direction of movement of an own vehicle, in a system which carries out driving support of a vehicle, turning control of the own vehicle is performed by a support control unit in order to avoid a collision with the solid object. Then, the turning control by the support control unit is stopped by a turning control stop unit, in cases where a correlation between a vehicle state related to turning of the own vehicle and a value of a predetermined parameter related to the turning control does not belong to a range of normal state set in advance, after the turning control by the support control unit has been started. This stops excessive steering of a steering resulting from a low friction of a traveling road surface, so that a strange or uncomfortable feeling of a driver can be eliminated.