Steer-by-wire system with simplified control architecture

Solution Overview

Problem

Steer-by-wire steering systems have high complexity and costs due to redundant designs, particularly in rotor position sensors and control devices, which are essential for generating appropriate reaction forces but increase system redundancy and costs.

Innovation Solution

The system simplifies by using a single rotor position sensor and reducing the number of control devices, with the first control device determining rotor position information from a steering handle angle sensor in case of malfunction, and implementing galvanic isolation between circuits to enhance reliability, thereby reducing overall system complexity and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple rotor position sensors and control devices are used for redundant design, then system reliability is improved, but device complexity and manufacturing costs increase

Engineering Contradiction:

Improvesystem reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple rotor position sensors and control devices into a single integrated control device. The control device performs both steering angle measurement and rotor position detection functions, eliminating redundant components while maintaining system reliability through functional integration rather than physical redundancy

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The control device is designed with multi-functionality, serving as both the steering angle sensor and rotor position sensor. This universal component performs multiple functions that previously required separate dedicated sensors and control units, reducing overall system complexity while preserving reliability

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If multiple rotor position sensors and control devices are used for redundant design, then system reliability is improved, but manufacturing costs increase

Engineering Contradiction:

Improvesystem reliabilityVSAvoidmanufacturing costs

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the functions of multiple rotor position sensors and control devices into a single integrated control device. The control device performs both steering angle measurement and rotor position detection functions, eliminating redundant components while maintaining system reliability through functional integration rather than physical redundancy

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and eliminates redundant components from the system by determining rotor position information directly from steering angle measurements. This removes the need for separate rotor position sensors and their associated control devices, reducing part count and manufacturing complexity

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If a single rotor position sensor is used instead of redundant sensors, then device complexity is reduced, but reliability may deteriorate

Engineering Contradiction:

Improvedevice complexityVSAvoidsystem reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The control device is designed with multi-functionality, serving as both the steering angle sensor and rotor position sensor. This universal component performs multiple functions that previously required separate dedicated sensors and control units, reducing overall system complexity while preserving reliability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses feedback from the steering angle measurement to determine rotor position information. The control device continuously monitors steering angle and uses this information to infer rotor position, creating a feedback mechanism that maintains reliability without requiring redundant physical sensors

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP4026752B1Steer-by-wire steering system for a motor vehicle with a simplified control architecture

Publication Date: 2024.07.10 VOLKSWAGEN AG

Figure 1

AI summary

The invention relates to a steer-by-wire steering system (10) for a motor vehicle (1), comprising: - a reaction force actuator (12) mechanically connected to a steering handle (18); - a rotor position sensor (52) for detecting the rotor position of the reaction force actuator (12); - a steering handle angle sensor (14); - at least one first control unit (16) for controlling the reaction force actuator (12); wherein the first control unit (16) is configured to determine rotor position information based on a measured value from the steering handle angle sensor (14) in the event of a malfunction of the rotor position sensor (52). The invention further relates to a method for operating such a steering system (10).