Superimposed Steering System Speed Signal Filtering
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Solution Overview
Problem
In superimposed steering systems, the time delay in speed signal filtering can cause disruptive steering wheel movement when the vehicle is braked quickly, as the speed signal's delay leads to movement after the vehicle has stopped.
Innovation Solution
The method involves adjusting the time delay based on driving speed, using either multiple filters with different time delays for specific speed ranges or an adaptive filter with a variable time constant, ensuring the speed is quickly incorporated into the steering ratio calculation, preventing steering wheel movement when the vehicle is stationary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed time delay filter is used for speed signal processing, then the steering ratio can be smoothly adjusted at high speeds, but disruptive steering wheel movement occurs during rapid braking
Solution Approach 1:
The filter time delay is made dynamic rather than fixed. The control unit adjusts the filter time delay based on the relationship between current speed and target speed: using a first (longer) time delay when speed difference is large to ensure stability, and a second (shorter) time delay when speed difference is small to enable rapid response. This dynamic adjustment eliminates steering wheel movement during rapid braking while maintaining smooth steering ratio adjustment during normal operation.
Solution Approach 2:
The patent changes the parameter of filter time delay based on operating conditions. By monitoring the speed difference and selectively applying different time delay values, the system adapts to varying driving scenarios, using longer delays for stability during large speed changes and shorter delays for responsiveness during minor adjustments or rapid braking events.
2Speed
If the filter time delay is reduced for faster response, then steering ratio adapts quickly during rapid braking, but steering ratio becomes unstable at high speeds
Solution Approach 1:
The system dynamically selects filter time delay values based on real-time speed conditions. During rapid braking with large speed differences, the control unit applies the first (longer) time delay to maintain stability. When the vehicle approaches target speed or during minor speed variations, it switches to the second (shorter) time delay for faster response. This conditional dynamic adjustment resolves the contradiction between response speed and stability.
Solution Approach 2:
The patent implements parameter changes by selecting different filter time delay values according to the magnitude of speed difference. This adaptive parameter selection allows the system to optimize between response speed and stability based on actual operating conditions, using longer delays when stability is critical and shorter delays when rapid adaptation is needed.
Data Source
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AI summary
The invention relates to a method for activating a superimposed steering system (10), a superimposed steering system (10), a controller (22), a computer program, and a computer program product. In the method, a steering ratio occurs as a function of the driving speed, wherein the degree of a chronological delay is adjusted as a function of the driving speed.