Steering Assist Control Using Predicted Lateral Deviation

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Solution Overview

Problem

Conventional vehicle steering systems increase steering control amounts based on lane width deviations, imposing a burden on drivers when they intentionally steer away from the target traveling line, particularly on curved roads.

Innovation Solution

A vehicle steering system that includes a steering control amount limiting unit to calculate and limit the steering control based on detected steering force and predicted lateral deviation fluctuation, adjusting the control amount according to the driver's intent and the predicted deviation from the target traveling line.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the steering control amount is increased based on lane width deviation to improve vehicle following of target traveling line, then the vehicle tracking accuracy is improved, but the driver burden increases when the driver intentionally steers away from the target traveling line

Engineering Contradiction:
Improvevehicle tracking accuracyVSAvoiddriver operation ease
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The steering control amount limiting unit dynamically adjusts the steering control amount based on detected steering force and predicted lateral deviation fluctuation. When the driver applies steering force indicating intentional deviation (e.g., wanting to drive on inner side of curve), the system reduces the steering control amount to match driver intent. This dynamic adjustment resolves the contradiction by making the system adaptive to driver intentions rather than rigidly enforcing target line following.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of steering control amount based on detected steering force magnitude and predicted lateral deviation fluctuation. By monitoring steering force as an indicator of driver intent and adjusting the control amount parameter accordingly, the system can reduce intervention when the driver intentionally wants to deviate from the target traveling line, thus improving ease of operation while maintaining tracking accuracy when appropriate.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the steering control amount is increased to improve vehicle following of target traveling line, then the lane keeping performance is improved, but the interference between driver steering and steering assistance increases

Engineering Contradiction:
Improvelane keeping performanceVSAvoidsteering interference
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system uses feedback from the steering force detection unit to monitor driver intentions in real-time. When the driver applies steering force indicating intentional deviation from the target traveling line, the feedback loop triggers the steering control amount limiting unit to reduce the steering control amount. This feedback mechanism allows the system to adapt to driver intentions and reduce harmful interference while maintaining lane keeping performance when the driver is not intentionally deviating.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The predicted lateral deviation fluctuation amount calculation performs preliminary assessment of driver intent before the steering assistance is applied. By predicting whether the driver intends to deviate from the target traveling line based on current steering force and vehicle state, the system can preemptively adjust the steering control amount to avoid harmful interference, thus improving lane keeping performance without causing driver annoyance.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4159566B1Vehicle steering system
Publication Date: 2025.11.05 MITSUBISHI ELECTRIC CORP
  • EP4159566B1 patent drawingFigure 1
  • EP4159566B1 patent drawingFigure 2
  • EP4159566B1 patent drawingFigure 3

AI summary

Provided is a vehicle steering system capable of reducing the burden on a driver. The vehicle steering system includes: a steering control amount calculation unit (11) for calculating a steering control amount for causing a vehicle to follow a target traveling line; a predicted lateral deviation fluctuation amount calculation unit (12) for calculating a predicted lateral deviation fluctuation amount predicted as a lateral deviation fluctuation amount with respect to the target traveling line of the vehicle; and a steering control amount limiting unit (13) for calculating a steering control amount limit value on the basis of a steering force and the predicted lateral deviation fluctuation amount, and outputting a limited steering control amount to which the steering control amount is limited by the steering control amount limit value, and in a case where the absolute value of the steering force is the same, when the absolute value of the predicted lateral deviation fluctuation amount is large, the steering control amount limiting unit (13) sets the steering control amount limit value to a value larger than or equal to that when the absolute value of the predicted lateral deviation fluctuation amount is small.