Steer-by-Wire Redundant Power and Sensor Architecture
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Solution Overview
Problem
Steer-by-wire steering systems for motor vehicles face challenges in balancing cost and reliability to meet safety requirements, as existing systems often require a compromise between fault tolerance and the number of redundant components.
Innovation Solution
A steer-by-wire steering system with a redundant power supply for the steering actuator and a feedback actuator connected to a single power supply, utilizing a second external steering angle sensor independent of the feedback actuator, and a private or motor vehicle communication channel for redundant communication, allowing the system to maintain functionality even if one power supply or communication channel fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant components are added to improve fault tolerance, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The system divides the steering system into functionally independent modules: a steering actuator with dual power supplies, a feedback actuator, and dual steering angle sensors. Each module can operate independently or fail without affecting the entire system, allowing selective redundancy where needed rather than redundant duplication of all components.
Solution Approach 2:
The patent implements partial redundancy by providing redundant power supply only for the steering actuator (not the feedback actuator) and using a second steering angle sensor that can replace the feedback actuator's sensor function. This partial redundancy approach achieves required safety objectives while avoiding unnecessary component duplication.
2Reliability
If redundant power supply is implemented for the steering actuator, then reliability is improved, but device complexity increases
Solution Approach 1:
The power supply system is segmented into a first power supply connected to the feedback actuator and a second power supply connected to the steering actuator. This segmentation allows independent failure isolation - if one power supply fails, the other can continue to power its associated actuator, ensuring continuous steering functionality without requiring redundant power supplies for all components.
3Reliability
If a second steering angle sensor is added independent of the feedback actuator, then reliability is improved, but device complexity increases
Solution Approach 1:
The second steering angle sensor is designed with multi-functionality: it can serve as a backup for the feedback actuator's sensor function and also independently provide steering angle information to the control unit. This universal design allows a single additional sensor to provide both redundancy and alternative functionality, reducing the need for multiple specialized redundant components.
4Reliability
If redundant communication channels are implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The communication system is segmented into a first communication channel connecting the feedback actuator and a second communication channel connecting the steering actuator. This segmentation allows independent communication paths, so if one channel fails, the other can maintain system communication. The steering actuator can receive steering angle data from either channel, ensuring continuous operation.
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a steer-by-wire steering system (1) for motor vehicles, comprising a steering controller (6) electronically controlled according to a driver's steering command and acting on the steered wheels (7), and a feedback actuator (4) transmitting feedback from the street (70) to a steering wheel and having a first steering angle sensor (40), wherein the steering controller (6) has a redundant power supply (300, 301) and is connected to a first power supply (300) and a second power supply (301), and wherein the feedback actuator (4) is connected to the first power supply (300) and the steer-by-wire steering system comprises a second steering angle sensor (50) which is independent of the feedback actuator (4) and is connected to the second power supply (301).