Train Position Detection Using Off-Track LED Markers

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Solution Overview

Problem

Existing train automatic stop control devices are costly due to the need for ground coils installed within the railroad track, and they suffer from discrete position correction, leading to reduced accuracy.

Innovation Solution

A train automatic stop control device that calculates the current position using a device installed outside the railroad track, utilizing a relative distance between the train and an object installed outside the track, such as a camera or millimeter-wave/laser irradiation, for continuous position correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ground coils are installed within the railroad track to achieve train position detection, then position detection accuracy is improved, but installation cost increases and safety measures are required

Engineering Contradiction:
Improveposition detection accuracyVSAvoidinstallation cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Instead of installing detection devices (ground coils) on the track side, the patent inverts the approach by placing the detection object on the track and using an on-vehicle sensor to detect it. This eliminates the need for expensive ground coil installation while maintaining position detection accuracy.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces the magnetic field-based ground coil system with an optical detection system using a camera and LED markers. This substitution eliminates the need for complex electrical infrastructure within the track while achieving comparable or superior position detection precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Loss of information

If ground coils are installed within the railroad track, then position information can be obtained, but the installation requires advanced safety measures and higher cost

Engineering Contradiction:
Improveposition informationVSAvoidsafety risks
Core Design Contradiction:
Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the electrical/magnetic ground coil system with an optical detection system using cameras and LED markers. This eliminates safety risks associated with electrical equipment on the track while ensuring continuous position information is obtained.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of information

If ground coils are used for position correction, then position information can be obtained, but the position correction is discrete rather than continuous

Engineering Contradiction:
Improveposition informationVSAvoidposition correction accuracy
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent implements continuous position correction by placing multiple LED markers along the track and using an on-vehicle camera to detect them continuously. This provides uninterrupted position information throughout the train's journey, eliminating the discrete correction limitations of ground coils.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent divides the track into multiple segments with LED markers placed at regular intervals. This segmentation allows the camera to continuously detect position information at each marker point, creating a series of continuous position measurements that collectively provide accurate throughout the journey.

Inventive Principle:
Principle #1Segmentation

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 accurate and cost-effective train stopping at target positions with improved position correction accuracy, reducing installation costs and eliminating the need for on-vehicle coils and ground coils within the track.

Implementation Method 1

an imaging device to image the object; calculation means configured to calculate a relative distance between the target train and the object on the basis of the imaged object

Methodology Applied
Scientific EffectImage capture and processing: Photography

Implementation Method 2

a millimeter-wave irradiation device to irradiate the object with millimeter waves; calculate a relative distance between the target train and the object on the basis of the imaged object

Methodology Applied
Scientific EffectMillimeter-wave radiation: Microwave Radiation

Implementation Method 3

a laser irradiation device to irradiate the object with laser; calculate a relative distance between the target train and the object on the basis of the imaged object

Methodology Applied
Scientific EffectLaser irradiation: Laser

Data Source

PatentEP3492306B1Train automatic stop control device
Publication Date: 2022.11.23 HITACHI LTD
  • EP3492306B1 patent drawingFigure 1
  • EP3492306B1 patent drawingFigure 2
  • EP3492306B1 patent drawingFigure 3

AI summary

The purpose of the present invention is to propose a train automatic stop control device which enables continuous calculation of a relative distance between train and an object disposed in a railroad station as a device off of a railroad track in a railroad station such that the need for devices installed on the tracks can be eliminated to achieve cost reduction, and accuracy in detecting a current position of the train can be improved. This train automatic stop control device is equipped with: a speed/position calculation means for calculating a speed and a current position of the train; and a relative distance calculation means for calculating a relative distance between the train and an object disposed in a railroad station as a device off of a railroad track. The speed/position calculation means calculates the current position of the train from information input from the relative distance calculation means regarding the relative distance and the position of the object.