Rail Slippage Determination Using Multiple Transfer Functions
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Solution Overview
Problem
Existing methods for determining shifts in railway tracks are limited by their reliance on a single transfer function, which introduces biases and fails to accurately represent the intrinsic geometry of the rail, leading to incomplete correction of defects, especially those associated with specific frequency characteristics.
Innovation Solution
A method that uses multiple transfer functions to model the rail's absolute profile, decomposing it into a target route and straightening signal, allowing for precise determination of shifts at control points, thereby accounting for defects across an extended spectrum of wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single transfer function is used to model rail geometry, then the measurement process is simple, but the representation of rail intrinsic geometry is inaccurate and introduces bias
Solution Approach 1:
The patent segments the rail geometry representation by using multiple transfer functions (at least two) with different frequency characteristics instead of a single transfer function. Each transfer function captures different frequency components of the rail profile, allowing comprehensive representation of rail geometry across extended wavelength ranges while maintaining measurement accuracy.
2Device complexity
If a single transfer function with limited bandwidth is used, then the measurement device is simpler, but certain wavelength defects are filtered out and cannot be detected or corrected
Solution Approach 1:
The patent implements multi-functionality by designing the measurement system to perform multiple detection tasks across different wavelength ranges simultaneously. By combining multiple transfer functions with complementary frequency characteristics, the system can detect and characterize defects across an extended spectrum of wavelengths, making the measurement device versatile for various defect types while maintaining reasonable complexity.
3Ease of operation
If arrows are used to represent rail geometry, then small defects can be described relative to large distances, but the representation is not the most accurate possible and introduces bias in slippage calculation
Solution Approach 1:
The patent changes the parameters used to represent rail geometry by transitioning from relative arrow-based parameters to absolute domain parameters. By determining slippages directly in the absolute domain using multiple transfer functions, the method eliminates the bias introduced by the theoretical three-point measurement model while maintaining the ability to describe small defects relative to large distances through the transfer function framework.
Data Source
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AI summary
The invention relates to a method for determining the slippage of a railway track rail in the absolute domain, said rail being sampled at successive control points at which deflections have been obtained by means of distinct transfer functions. Furthermore, the method comprises the following steps: - modeling the rail by a signal called the absolute profile, estimated by means of said deflections obtained; - decomposing the estimated absolute profile into a first sub-signal called the intended track of the rail, representing the trajectory of the rail as adapted to meet improved rail operating conditions, and into a second sub-signal called the alignment of the rail, representing the deformations undergone by said intended track of the rail over time; - determining the slippage at said control points such that at each control point the sum of said slippage and said alignment of the rail is zero.