Steer-by-Wire Power Redundancy for Fail-Safe Steering Control

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Solution Overview

Problem

Steer-by-wire (SBW) systems in vehicles lack redundancy in electrical components, leading to a failure in steering operations when electrical components fail, as they lack mechanical backup, and existing redundant designs are costly and require complete separation of power supplies.

Innovation Solution

An electronic steering apparatus with dual power sources and sensors to diagnose failures, allowing fail-safe operation by controlling drive motors based on power state comparisons, reducing power consumption and maintaining stability without full power separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant electrical components are designed with complete separation of power supplies, then reliability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvesteering system reliabilityVSAvoidpower supply separation complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electrical system is segmented into multiple independent power supply paths. The patent implements separate power supply circuits for critical steering components, allowing independent power delivery to different subsystems. This segmentation enables the system to maintain operational capability even when one power path fails, thus improving reliability without requiring complete system redundancy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of implementing complete redundancy for all electrical components, the patent applies partial redundancy only to critical steering functions. The system provides excessive power capacity in essential areas while maintaining cost-effectiveness by avoiding full system duplication. This selective approach addresses the core reliability concern without proportionally increasing complexity across the entire system.

Inventive Principle:

Principle #16Partial or excessive action

2Reliability

If redundant electrical components are designed with complete separation of power supplies, then reliability is improved, but cost increases

Engineering Contradiction:

Improvesteering system reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the power supply architecture into modular segments, where critical components receive dedicated power paths while non-critical components share common power sources. This segmentation strategy reduces manufacturing costs by avoiding complete system duplication while maintaining reliability for essential steering functions through targeted power supply separation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different power supply quality levels to different system components. Critical steering components receive redundant, separated power supplies with higher reliability characteristics, while non-critical components use standard shared power supplies. This local differentiation optimizes cost by allocating redundancy resources only where they provide maximum safety benefit.

Inventive Principle:

Principle #3Local quality

3Weight of moving object

If mechanical connection structure is removed in SBW system, then weight is reduced and fuel efficiency is improved, but safety is worsened due to lack of mechanical backup

Engineering Contradiction:

Improvevehicle weightVSAvoidsteering safety

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent replaces mechanical connection structures with electrical control systems in the steer-by-wire architecture. By eliminating universal joints, pinion shafts, and other mechanical linkages between steering wheel and rack bar, the system reduces weight while maintaining steering functionality through motor-driven rack bar actuation controlled by electrical signals from sensors and ECUs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent segments the steering system into independent functional modules: steering wheel assembly, reaction motor, steering motor, rack bar, and ECU. This modular segmentation allows removal of unnecessary mechanical connections while maintaining system integrity through electrical coupling. Each module can be independently optimized for weight reduction while preserving overall steering safety through redundant electrical control paths.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12515732B2Electronic steering apparatus for vehicle and method of controlling same

Publication Date: 2026.01.06 HYUNDAI MOBIS CO LTD

AI summary

Disclosed herein is an electronic steering apparatus for a vehicle. The apparatus includes a first driver and a second driver configured to drive a drive motor by being supplied, respectively, with electric power from a first electric-power source and a second electric-power source, a first sensor and a second sensor configured to recognize states, respectively, of the first electric-power source and the second electric-power source, and states, respectively, of the first driver and second driver, a first output controller and a second output controller coupled to a vehicle control device, and a first processor and a second processor operatively coupled, respectively, to the first and second drivers, the first and second sensors, and the first output and second output controllers. The processors are configured to determine whether electric-power states of the first electric-power source and the second electric-power source are normal, by comparing the electric-power states with each other.