Steer-by-Wire Road-Excitation Feedback Optimization
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Solution Overview
Problem
In Steer by Wire (SbW) vehicles, the lack of mechanical connection between the steering wheel and wheels results in inadequate feedback of road excitations to the driver, making it difficult to discern individual road imperfections at high speeds due to overlapping vibrations.
Innovation Solution
A method and apparatus that optimizes the feedback by measuring and comparing the temporal progression of excitation at the tie rod with a target progression, adjusting controller and software functions to minimize deformation and time delay, thereby enhancing the transmission of road imperfection information to the driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical transmission of surface excitations is replaced by electrical signals in SbW system, then steering control precision is improved, but feedback of road excitations to driver is lost
Solution Approach 1:
The patent introduces a feedback generation unit that acts as an intermediary to synthesize road excitation feedback signals. This unit receives wheel position data and generates artificial feedback signals that simulate the mechanical transmission of road excitations, thereby compensating for the loss of direct mechanical feedback while maintaining the electrical signal transmission advantage
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously measures actual wheel positions and generates feedback signals that are fed back to the driver through the steering wheel. This closed-loop feedback system recreates the sensation of road excitations by processing wheel position data and generating appropriate force feedback signals
2Reliability
If feedback is transmitted electrically without mechanical connection, then system reliability is improved, but driver perception of road conditions deteriorates
Solution Approach 1:
The feedback generation unit serves as an intermediary that processes electrical wheel position data and transforms it into perceptible feedback signals. This intermediary component ensures that while the mechanical connection is eliminated for reliability, the information about road conditions is preserved and transmitted to the driver through synthesized feedback signals
Solution Approach 2:
The patent replaces the mechanical transmission system with an electrical signal processing system that includes sensors, controllers, and feedback generation units. This substitution maintains system reliability by eliminating mechanical wear and connection issues, while the feedback generation unit compensates for the loss of direct mechanical feedback by creating artificial road excitation signals
3Loss of information
If controller and software functions are optimized, then feedback quality is improved, but device complexity increases
Solution Approach 1:
The feedback generation unit is designed to perform multiple functions: it processes wheel position data, generates road excitation feedback signals, and adapts to different driving conditions. This multi-functional design consolidates several operations into a single unit, reducing overall system complexity while maintaining high feedback quality
Solution Approach 2:
The patent optimizes feedback quality by adjusting parameters such as feedback signal amplitude, frequency, and timing through software control. By parameterizing the feedback generation process, the system can adapt to different road conditions and driver preferences without requiring complex hardware modifications, thereby managing device complexity
Data Source
AI summary
A method is for optimizing at least one feedback into a steering system of a vehicle from a surface driven on by the vehicle. When the surface is driven on by the vehicle, a temporal progression of an excitation at a tie rod of the steering system by the surface and a temporal progression of the at least one feedback of the steering system are measured. A temporal target progression of the feedback is determined as a function of the measured temporal progression of the excitation. A measure for the optimization of the at least one feedback is determined as a function of a comparison of the temporal progression of the at least one feedback with the target temporal progression. The at least one feedback is optimized as a function of the measure.