DTW Algorithm for Railway Track-Circuit Signal Alignment

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Solution Overview

Problem

Existing methods for determining the relationship between track-circuit transmitted current signals and railway vehicle locations on a railway track are non-linear, requiring manual and impractical calibration methods, such as shunting, which are time-consuming and not adaptable to changing conditions.

Innovation Solution

The use of Dynamic Time Warping (DTW) algorithm to automatically align and calculate a reference curve from transmitted current signals from multiple railway vehicles, allowing for dynamic and adaptive determination of the relationship without human intervention, and enabling accurate location estimation with a confidence interval and safety margin.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual shunting calibration is used to determine the relationship between track-circuit current signals and railway vehicle location, then measurement precision is improved, but loss of time and operational disruption increase significantly

Engineering Contradiction:

Improvelocation estimation accuracyVSAvoidcalibration time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs self-calibration by automatically collecting current signal data from multiple railway vehicles passing through the track block and using the DTW algorithm to generate the reference curve without human intervention. This eliminates the need for manual shunting operations while maintaining calibration accuracy.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system collects current signal data from multiple railway vehicles in advance to build a comprehensive dataset that represents various operating conditions. This preliminary data collection enables the DTW algorithm to generate a robust reference curve that accounts for non-linear relationships and environmental variations.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If manual shunting calibration is performed to establish current-location relationship, then measurement precision is improved, but device complexity and operational complexity increase

Engineering Contradiction:

Improvelocation estimation accuracyVSAvoidcalibration process complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical shunting calibration process with an automated computational system. The DTW algorithm processes current signal data to generate the reference curve, eliminating the need for physical shunt placement and manual calibration procedures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The DTW algorithm serves as an intermediary that automatically processes raw current signal data from multiple railway vehicles and transforms it into a calibrated reference curve. This intermediary system eliminates the need for direct manual intervention in the calibration process.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a static reference curve is used for location estimation, then device complexity is reduced, but adaptability to changing track conditions deteriorates

Engineering Contradiction:

Improveadaptability to track condition changesVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system implements a dynamic reference curve that can be regenerated whenever track conditions change. By continuously monitoring current signal data from passing railway vehicles and updating the reference curve using the DTW algorithm, the system adapts to variations in rail resistance, temperature, and other environmental factors.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses feedback from current signal measurements of passing railway vehicles to detect changes in track conditions. When deviations from the expected current-location relationship are detected, the system triggers regeneration of the reference curve to maintain accuracy under new conditions.

Inventive Principle:

Principle #23Feedback

4Measurement precision

If linear relationship assumption is used between current signal and vehicle location, then device complexity is reduced, but measurement precision deteriorates due to position errors

Engineering Contradiction:

Improvelocation estimation accuracyVSAvoidrelationship modeling complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent acknowledges and accommodates the non-linear (curved) relationship between current signal and vehicle location by using the DTW algorithm to generate a reference curve that captures the actual non-linear behavior. This eliminates position errors that would result from assuming a linear relationship.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS11577763B2Method and controller for determining the relationship between a track-circuit transmitted current signal and a railway vehicle location on a railway track

Publication Date: 2023.02.14 KB SIGNALING INC

AI summary

Disclosed is a method for determining the relationship between a track-circuit current signal and a railway vehicle location, including: sending, by a track circuit, current signal across a railway track block; measuring the current signal for different railway vehicles running successively on the railway track block; aligning the measured current signals and calculating a reference curve as the average value of all the aligned curves by using a Dynamic Time Warping algorithm, this reference curve representing the relationship between the track-circuit current signal and the railway vehicle location on the railway track block.