Rail Braking Parameter Modeling for Wheel-Rail Adhesion
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Solution Overview
Problem
Current methods for determining braking-behavior-relevant parameters in rail vehicle braking systems lack precision, especially in simulating realistic scenarios such as wheel-slide protection acceptance tests, leading to inefficiencies and increased costs in real vehicle testing.
Innovation Solution
A method utilizing a physical model that accounts for the influence of leading wheels on adhesion between trailing wheels and rails, including the effects of liquid on the rail, to determine precise braking-behavior-relevant parameters, such as adhesion characteristic curves, which can be used to simulate various test conditions like those with a water-soap mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a physical model accounting for leading wheel influence is used, then measurement precision of braking parameters is improved, but device complexity increases
Solution Approach 1:
The patent introduces a physical model that acts as an intermediary between the leading wheel's liquid-reducing action and the trailing wheel's adhesion characteristics. This model includes auxiliary characteristic curves (dry rail adhesion, wet rail adhesion) and a moisture value that mediates the complex interaction, enabling precise parameter determination without directly modeling every physical detail of liquid transfer between wheels.
2Reliability
If realistic test scenarios with liquid spray are simulated, then reliability of braking system testing is improved, but loss of time and resources increases
Solution Approach 1:
The patent creates a virtual copy of the realistic braking scenario using a physical model in simulation. Instead of performing actual vehicle tests with liquid spray on tracks, the invention replicates the essential physics through auxiliary characteristic curves and moisture values, producing equivalent test results without the time-consuming and resource-intensive real-world experiments.
3Manufacturing precision
If the influence of leading wheels on liquid distribution is considered, then manufacturing precision of test conditions is improved, but ease of operation decreases
Solution Approach 1:
The patent manages the complexity of modeling leading wheel influence by changing parameters rather than solving complex differential equations. The model uses a moisture value parameter that ranges from 0 to 1, and auxiliary characteristic curves that pre-compute adhesion relationships. This transforms a complex physical problem into a manageable parameter-based calculation that remains precise but is easier to operate.
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
Enables highly realistic simulation of wheel-slide protection acceptance tests, reducing the need for complex and expensive real vehicle tests by providing precise control parameters for slip controllers, ensuring compliance with approval standards.
Implementation Method 1
The liquid reduction can be brought about, for example, by friction of the leading wheel on the rail traveled on or by liquid adhering to or remaining on the rotating leading wheel
Implementation Method 2
liquid adhering to or remaining on the rotating leading wheel
Data Source
AI summary
A method for determining at least one braking-behavior-relevant parameter relevant to the open-loop or closed-loop control of a braking system (210) of a rail vehicle (200). A physical model (PHYSM) is used in determining the at least one braking-behavior-relevant parameter, the physical model taking into account the influence of a wheel (10) which leads a wheel (20) to be braked (20), specifically with respect to an influence effect which the leading wheel (10) has on the traction between the trailing wheel (20) to be braked and the rail (30).