Steering Reaction Control for Stable Vehicle Reversing

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Solution Overview

Problem

Existing vehicle steering systems face challenges in stabilizing vehicle behavior during backward travel and providing stable steering feedback, especially when the driver is visually checking the surroundings, leading to potential instability and difficulty in recognizing steering angles.

Innovation Solution

A vehicle steering device with a control unit that adjusts turning ratio gains based on vehicle speed and sets target turning angles to stabilize behavior, applying steering reaction forces and controlling wheel operation within mechanically determined maximum turning angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If the driver visually checks safety behind the vehicle during backward traveling, then the driver can monitor the surroundings, but the driver is likely to lose the steering posture and vehicle behavior becomes unstable

Engineering Contradiction:
Improvevisibility of surroundingsVSAvoidvehicle behavior stability
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The patent changes the turning ratio parameter based on vehicle speed and traveling direction. During backward traveling, a larger turning ratio is applied to amplify the relationship between steering angle and wheel angle, providing stronger steering feedback to the driver. This helps the driver maintain steering posture and control while visually checking surroundings, resolving the contradiction between monitoring visibility and maintaining vehicle stability.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the turning ratio is reduced for low-speed driving, then the steering supplementary force is reduced, but the driver has difficulty recognizing the steering angle at which the wheel is near zero

Engineering Contradiction:
Improvesteering operationVSAvoidsteering angle recognition
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent dynamically adjusts the turning ratio parameter based on vehicle speed and traveling direction. During backward traveling at low speed, the system applies a larger turning ratio to enhance steering feedback and improve the driver's ability to recognize steering angles. This resolves the contradiction by adapting the parameter to the specific operating condition where angle recognition is critical.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the steering supplementary force is simply reduced at low-speed driving, then the steering operation becomes easier, but it is difficult for the driver to recognize a steering angle at which the rudder angle is near zero

Engineering Contradiction:
Improvesteering operationVSAvoidsteering angle information
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent implements dynamic parameter adjustment of the turning ratio based on vehicle speed and traveling direction. During backward traveling, the system increases the turning ratio to provide enhanced steering feedback that helps the driver recognize when the wheel angle is near zero. This resolves the information loss problem while maintaining ease of operation through adaptive parameter control.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3978338B1Vehicular steering device
Publication Date: 2026.04.22 NSK LTD
  • EP3978338B1 patent drawingFigure 1
  • EP3978338B1 patent drawingFigure 2
  • EP3978338B1 patent drawingFigure 3

AI summary

To provide a vehicle steering device capable of stabilizing behavior of a vehicle when traveling backward. A vehicle steering device includes a reaction force device configured to apply steering reaction force to a wheel, a drive device configured to turn tires in accordance with steering of the wheel, and a control unit configured to control the reaction force device and the drive device. The control unit includes a turning ratio map unit configured to set a turning ratio gain in accordance with the vehicle speed of a vehicle, and a target turning angle generation unit configured to generate a target turning angle by multiplying the steering angle of the wheel by the turning ratio gain. The turning ratio gain at backward traveling of the vehicle is equal to or larger than the turning ratio gain at forward traveling of the vehicle.