Steering Wheel Actuator Eddy Current Damping for Feedback Failure
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Solution Overview
Problem
In steer-by-wire steering apparatuses, the lack of a direct mechanical connection between the steering wheel and the wheels poses a risk of undesirably strong steering movements if the feedback device fails, potentially leading to loss of control of the vehicle.
Innovation Solution
The introduction of an eddy current device that generates resistance to the rotation of the steering axle, providing artificial feedback and acting as a redundancy in case of feedback device failure, thereby reducing the risk of strong steering movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a feedback device is used to provide artificial steering feel in a steer-by-wire system, then the driver receives feedback on wheel-road interface, but the steering axle can be turned very easily with low frictional forces when the feedback device fails or is inactive
Solution Approach 1:
The patent introduces an eddy current device that generates electromagnetic damping forces to provide resistance to steering axle rotation. This device acts as a pre-prepared safety mechanism that automatically activates when the feedback device fails, cushioning against uncontrolled steering movements by creating frictional resistance through electromagnetic fields in the conducting unit
Solution Approach 2:
The eddy current device serves as an intermediary between the steering axle and the driver's steering input. It introduces electromagnetic damping as a mediating force that resists uncontrolled rotation, bridging the gap left by the failed feedback device and preventing direct mechanical over-rotation of the steering axle
2Reliability
If the feedback device is made redundant to improve safety, then loss of control risk is reduced, but the device complexity increases
Solution Approach 1:
The patent replaces a purely mechanical feedback device redundancy approach with an electromagnetic eddy current damping system. Instead of duplicating complex mechanical feedback components, the invention uses electromagnetic fields generated by magnets and conducting units to provide damping resistance, simplifying the overall system architecture while maintaining safety redundancy
Solution Approach 2:
The eddy current device changes the physical parameters of the steering system by introducing electromagnetic damping forces. The resistance generated depends on the rotational speed of the steering axle and the strength of the magnetic field, providing variable damping that adapts to different steering conditions without requiring complex mechanical adjustments
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
The eddy current device effectively reduces the risk of loss of control by maintaining resistance to the steering axle even in the absence of a functioning feedback device, thereby stabilizing vehicle steering.
Implementation Method 1
an eddy current device (23) is provided which generates a resistance for the rotation of the steering axle (2) about its longitudinal axle (4)
Data Source
AI summary
The disclosure relates to a steering wheel actuator unit for a steer-by-wire steering apparatus for a motor vehicle and having a steering axle, wherein a free end of the steering axle is designed for arranging a steering wheel and the steering axle is rotatably mounted about its longitudinal axle, the steering wheel actuator unit comprising at least one feedback device which acts on the steering axle to realize a predetermined torque and/or a predetermined damping, and a spindle device connected to the steering axle for providing end stops for the rotational movement of the steering axle. In order to be able to reduce and/or avoid incorrect operation in case of failure of the feedback device, the steering wheel actuator unit further comprising an eddy current device which generates a resistance for the rotation of the steering axle about its longitudinal axle.