Steer-by-Wire Steering Angle Control for Driver Override Feedback

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Solution Overview

Problem

Existing steer-by-wire steering systems face challenges in coordinating driver inputs with driver assistance system inputs due to mechanical decoupling, leading to complex coordination between driver and assistance system steering torques.

Innovation Solution

A steer-by-wire steering system with an integrated steering angle controller that receives target angles from driver assistance systems and generates adjustable torques, allowing drivers to feel and override recommendations, with optional user-adjustable torque limits and multiple assistance system integration via a bus system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the steering column module and steering gear are mechanically decoupled, then the driver assistance system can independently control steering torques, but the coordination between driver inputs and assistance system inputs becomes complex

Engineering Contradiction:
Improveautonomous steering control capabilityVSAvoidcoordination complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent introduces a steering angle controller as an intermediary component that receives target steering angles from the driver assistance system and translates them into actuator control signals. This mediator simplifies the coordination between driver inputs and assistance system inputs by converting torque-based control into position-based control, reducing the complexity of mechanical decoupling coordination

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical connection between steering column module and steering gear with an electronic control system. The steering angle controller electronically transmits target angle information to the actuator, substituting the complex mechanical coordination with a simpler electronic control architecture that maintains driver assistance functionality while reducing coordination complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If a position controller in the steering gear prioritizes between driver inputs and assistance system inputs, then coordination becomes manageable, but the driver's direct control over steering is reduced

Engineering Contradiction:
Improvecoordination manageabilityVSAvoiddriver control authority
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent implements a feedback mechanism where the steering angle controller receives actual steering angle information from the rotary angle sensor and compares it with the target steering angle. This feedback loop enables the system to automatically adjust the actuator output to achieve the desired steering angle, maintaining driver control authority while managing coordination through intelligent control algorithms rather than mechanical prioritization

Inventive Principle:
Principle #23Feedback

3Loss of information

If the steering angle controller generates torque recommendations, then the driver receives clear guidance, but the driver must apply additional force to override recommendations when desired

Engineering Contradiction:
Improvesteering guidance clarityVSAvoidoverride effort
Core Design Contradiction:
Loss of informationVSEase of operation

Solution Approach 1:

The patent changes the control parameter from torque generation to position control. The steering angle controller generates target steering angles based on driver assistance system inputs, and the actuator adjusts the steering angle to match these targets. This parameter change allows the system to provide clear steering guidance through angle recommendations while reducing the force required for drivers to override recommendations, as position adjustment requires less effort than torque counteraction

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Simplifies steering adjustment by providing clear feedback and allowing drivers to easily follow or override assistance system recommendations, enhancing user control and system integration.

Implementation Method 1

The actuator is, for example, an electric servo motor

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Data Source

PatentEP4137384B1Steer-by-wire steering system for a vehicle and method for operating a steer-by-wire steering system
Publication Date: 2025.12.10 VOLKSWAGEN AG
  • EP4137384B1 patent drawingFigure 1

AI summary

The invention relates to a steer-by-wire steering system (1) comprising a steering handle (2), a steering column module (3) and a steering gear (4), wherein the steering column module (3) and the steering gear (4) are connected electronically, wherein a rotation angle sensor (6) and an actuator (7) for generating a counter-torque on the steering handle (2) are arranged in the steering column module (3), wherein a steering angle controller (9) is arranged in the steering column module (3), wherein the steering angle controller (9) is connected electronically to at least one driver assistance system (17), wherein the steering angle controller (9) is configured to receive a target angle (ϕtarget) from the at least one driver assistance system (17) and to generate a torque for setting the target angle (ϕtarget) via the actuator (7) or a further actuator, and a method for operating a steer-by-wire steering system (1).