Steering System With Dynamic Neutral Position

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Solution Overview

Problem

Conventional Lane Keeping Support (LKS) systems alter the steering characteristics when the vehicle deviates from the ideal lane, causing unfamiliar and irritating changes in steering forces felt by the driver.

Innovation Solution

The system sets the zero position of the steering to a reference steering angle that shifts with the lane curvature, maintaining constant steering characteristics by applying restoring forces only when the vehicle deviates from the ideal lane, with the assistance torque dependent on the deviation level and regulated by torque sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LKS systems apply additional guidance torque when vehicle deviates from lane, then lane keeping support is improved, but steering characteristics change causing unfamiliar and irritating forces

Engineering Contradiction:
Improvelane keeping supportVSAvoidsteering characteristics
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies the dynamics principle by making the zero position of the steering characteristic dynamic rather than fixed. The zero position shifts continuously according to the reference steering angle calculated from lane curvature and vehicle position, allowing the steering system to adapt to lane changes while maintaining consistent steering feel for the driver. This resolves the contradiction by enabling lane keeping support without creating unfamiliar steering forces.

Inventive Principle:
Principle #15Dynamics

2Reliability

If support torque is reduced to provide corrective feedback, then lane deviation correction is improved, but steering forces become unnatural

Engineering Contradiction:
Improvelane deviation correctionVSAvoidsteering forces
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies parameter changes by modifying the zero position parameter of the steering characteristic curve based on the reference steering angle. Instead of changing the support torque magnitude to provide correction, the system shifts the zero position parameter dynamically, which provides lane deviation correction while maintaining natural steering forces that feel consistent to the driver.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If steering characteristic zero position is fixed, then conventional steering feel is maintained, but lane curvature adaptation is lost

Engineering Contradiction:
Improvesteering feelVSAvoidlane curvature adaptation
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent makes the zero position of the steering characteristic dynamic by continuously updating it according to the reference steering angle, which is calculated from lane curvature and vehicle position data. This allows the system to adapt to different lane curvatures while maintaining a consistent and natural steering feel for the driver, resolving the contradiction between fixed steering feel and lane curvature adaptation.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP1910150B1Steering system for motor vehicles, featuring a sliding neutral position
Publication Date: 2008.12.10 ROBERT BOSCH GMBH
  • EP1910150B1 patent drawingFigure 1
  • EP1910150B1 patent drawingFigure 2~4
  • EP1910150B1 patent drawingFigure 3

AI summary

The invention relates to a servo steering system for motor vehicles, comprising a steering adjuster (11) by means of which a supporting moment (Mu) can be applied to the steering mechanism (12) of the vehicle (1), a lane recognition system (13) for recognizing information regarding the course of the lane, a reference model (3) that calculates a reference steering angle (dRef) in accordance with the data received from the lane recognition system (13), and a transmitting member (16) that determines the supporting moment (Mu) transmitted to the steering mechanism (12) by the steering adjuster (11) in accordance with the driving condition. The transmitting member (16) is designed such that the neutral position of the steering characteristics (17) is identical to the reference steering angle (dRef) and moves along with the reference steering angle (dRef) in accordance with the course (15) of the lane.