Steer-By-Wire Steering Backup Signal Path for Electronics Failure
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Solution Overview
Problem
Steer-by-wire steering systems face reliability issues due to potential failures in control electronics, which can disrupt the detection and implementation of driver steering movements, particularly in the absence of mechanical connections between the steering wheel and vehicle axles.
Innovation Solution
A steer-by-wire steering system incorporating a steering wheel actuator with an electric motor that can function as a generator to provide measurement values to the axle control unit, even in the event of control electronics failure, using an equivalent circuit with current sensors and a logic circuit to ensure operation, allowing the axle actuator to maintain steering functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steer-by-wire steering systems use redundant control electronics to ensure reliability, then system reliability is improved, but the system becomes vulnerable to complete failure when control electronics fail
Solution Approach 1:
The patent introduces an intermediary mechanism (the equivalent circuit connected to the steering wheel actuator) that can detect steering wheel movements and transmit this information to the axle actuator when control electronics fail. This intermediary serves as a backup communication path that bypasses the failed control electronics, resolving the contradiction by providing reliability through an alternative detection method rather than through redundant complex electronics.
Solution Approach 2:
The steering wheel actuator's electric motor serves dual purposes: it functions as a motor during normal operation and as a generator during failure modes to produce detectable electrical signals that indicate steering wheel movements. This self-service capability allows the system to maintain functionality using its own components rather than requiring separate redundant systems, thereby improving reliability without proportionally increasing device complexity.
2Ease of operation
If mechanical connections are removed between steering wheel and axle to enable steer-by-wire functionality, then steering precision and control flexibility are improved, but the system loses inherent mechanical feedback and reliability
Solution Approach 1:
The patent replaces the removed mechanical connection with an electrical signal transmission system. The equivalent circuit converts steering wheel movements into electrical signals that are transmitted to the axle actuator, substituting the mechanical feedback path with an electrical one. This maintains the steer-by-wire flexibility while restoring reliability through electronic detection and transmission capabilities.
Solution Approach 2:
The system implements an electrical feedback mechanism where the equivalent circuit continuously monitors steering wheel actuator movements and transmits this information to the axle actuator. This feedback loop replaces the mechanical feedback that would naturally exist with direct mechanical connections, maintaining system reliability through active electronic monitoring and response.
3Device complexity
If control electronics are simplified to reduce complexity, then system robustness is improved, but the system cannot detect and respond to steering movements during failure modes
Solution Approach 1:
The patent merges the detection and signal generation functions into the existing steering wheel actuator's electric motor. The same motor that drives the steering wheel also generates electrical signals during failure modes that indicate steering movements. This merging eliminates the need for separate detection electronics, reducing overall system complexity while maintaining reliability during failures.
Solution Approach 2:
The electric motor in the steering wheel actuator serves multiple functions: it acts as a motor during normal operation to position the steering wheel, and as a generator during failure modes to produce detectable electrical signals that indicate steering movements. This multi-functionality reduces the need for separate components, simplifying the control electronics while ensuring reliability across different operational states.
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
This configuration enhances the reliability of the steer-by-wire steering system by enabling continued operation even without functional control electronics, ensuring that driver-intended steering movements are converted into vehicle axle movements, thus maintaining system functionality during failures.
Implementation Method 1
the steering wheel electric motor can also work as a generator in the event of a failure of control electronics of the steer-by-wire steering system, so that a measurement value can be determined depending on the steering movement performed on the steering wheel
Data Source
AI summary
A steer-by-wire steering system for a vehicle is provided that includes a steering wheel actuator for moving and detecting movements of a steering wheel of the vehicle. The steering wheel actuator includes a steering wheel electric motor. The steer-by-wire steering system further includes an axle actuator for moving and detecting movements of wheels of an axle of the vehicle. The axle actuator includes an axle electric motor and an axle control unit. The steer-by-wire steering system an equivalent circuit, which measures a current induced by the steering wheel electric motor and provides the axle control unit with at least one measurement value depending on the induced current for controlling the axle electric motor.