Electronic Steering Coupling Resistance for Fault-Tolerant Control
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Solution Overview
Problem
Electronic steering systems in vehicles lack sufficient redundancy and precision in lateral control, leading to rapid degradation in functionality upon fault occurrence, causing uncomfortable transitions and loss of vehicle control.
Innovation Solution
Implementing a redundant steering system with electrical and mechanical damping devices to vary coupling resistance between the road wheel actuator and steerable wheels, allowing dynamic adjustment based on driving conditions and fault detection, utilizing auxiliary steering through electric motors and deceleration devices for precise lateral control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanical link between steering wheel and road wheel is eliminated to enable electronic steering, then steering system flexibility and control precision are improved, but system reliability deteriorates due to lack of mechanical redundancy
Solution Approach 1:
The patent introduces a coupling device as an intermediary component between the road wheel actuator and the steerable road wheel. This coupling device provides mechanical redundancy while maintaining electronic steering flexibility, resolving the contradiction between adaptability and reliability by mediating the connection in a controllable manner
Solution Approach 2:
The coupling device is designed with variable coupling resistance that can be dynamically adjusted based on driving conditions and fault detection. This dynamic adjustment capability allows the system to adapt between different operational modes (normal operation vs. fault condition), thereby maintaining both flexibility and reliability
2Reliability
If coupling resistance is increased to improve fault tolerance and continuity of control, then system reliability is improved, but lateral control precision deteriorates during normal operation
Solution Approach 1:
The coupling resistance is designed to be variable rather than fixed. During normal operation, the coupling resistance is kept low to maintain precise lateral control. Upon fault detection or under specific driving conditions, the coupling resistance can be increased to improve fault tolerance and control continuity, thus adapting between precision and reliability requirements
Solution Approach 2:
The system changes the coupling resistance parameter dynamically based on operational state. By adjusting this key parameter, the system can optimize for either precision (low resistance) or reliability (high resistance) depending on the current driving conditions and detected system state
3Reliability
If electrical damping device is used to vary coupling resistance for improved control continuity, then system reliability is improved, but device complexity increases
Solution Approach 1:
The electrical damping device is integrated into the existing road wheel actuator system, serving multiple functions: it provides variable coupling resistance for control continuity, assists in fault detection, and can operate in conjunction with the mechanical coupling device. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in overall system complexity
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
Enhances precision and continuity of vehicle control by adapting coupling resistance to driving situations, ensuring stable operation even with faults, and maintaining high precision in lateral control through auxiliary steering systems.
Implementation Method 1
controlling an electrical damping device to increase an electrical resistance of an electric motor of the road wheel actuator
Implementation Method 2
the electrical short-circuit device to short circuit windings of the electric motor to generate a first electrical resistance of the electric motor that changes a coupling resistance
Implementation Method 3
a mechanical damping device in a coupling path between the road wheel actuator and the steerable road wheel, the mechanical damping device configurable to vary the coupling resistance
Data Source
AI summary
Disclosed examples include setting a coupling resistance between a road wheel actuator and a steerable road wheel of a vehicle at a first time by controlling an electrical damping device to increase an electrical resistance of an electric motor of the road wheel actuator; and changing the coupling resistance between the road wheel actuator and the steerable road wheel at a second time by controlling the electrical damping device to further increase the electrical resistance of the electric motor of the road wheel actuator.