Pantograph Inspection via Ground-Level Stereo Vision

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Solution Overview

Problem

Current video inspection systems for pantographs along overhead contact lines face challenges in obtaining reliable three-dimensional models, especially at high speeds, and require complex and costly infrastructure, failing to accurately measure contact strip thickness and identify cracks.

Innovation Solution

A system utilizing a plurality of monitoring stations with stereo video cameras and LED illumination, positioned alongside the tracks, which acquire images of the pantograph's contact strips and horns, allowing for three-dimensional model reconstruction independent of locomotive speed, using CMOS or CCD sensors and laser telemeters for precise detection and illumination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If video cameras are positioned above the moving pantograph to ensure reliable measurements, then measurement reliability is improved, but device complexity and installation cost increase

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of positioning cameras above the pantograph (conventional approach), the invention inverts the arrangement by placing cameras on the ground level alongside the track. This inversion simplifies installation while maintaining measurement reliability through stereo vision technology and proper geometric configuration of the camera system.

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

Solution Approach 2:

The invention introduces laser telemeters as intermediary devices that work in conjunction with the ground-level cameras. The telemeters provide auxiliary measurement data that compensates for the non-ideal positioning of cameras, enabling reliable three-dimensional reconstruction without requiring cameras to be mounted above the pantograph.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If a single video camera is used for pantograph inspection, then device complexity is reduced, but measurement precision and crack detection capability deteriorate

Engineering Contradiction:
Improvesystem simplicityVSAvoidcontact strip thickness measurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The invention transitions from two-dimensional single-camera imaging to three-dimensional stereo vision by employing pairs of cameras at each monitoring station. This dimensional change enables precise thickness measurement and crack detection while maintaining relatively simple ground-level installation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If video cameras are used to reconstruct three-dimensional model of pantograph, then inspection capability is improved, but installation cost and infrastructure complexity increase

Engineering Contradiction:
Improveinspection capabilityVSAvoidinfrastructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention inverts the conventional approach by placing cameras on the ground rather than mounting them on overhead structures. This eliminates the need for complex installation infrastructure while maintaining the ability to reconstruct three-dimensional pantograph models through stereo vision and laser telemeter integration.

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

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 reliable three-dimensional model reconstruction of pantographs, including contact strips and horns, without speed dependency, using existing infrastructure, reducing costs and complexity, and providing accurate wear and crack detection for maintenance planning.

Implementation Method 1

a first illumination means (4) for illuminating a first overhead zone in which a portion of the pantograph (100) passes

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 2

a first acquisition means (5) for acquiring images of the first overhead zone

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 3

detection means (3) for detecting passage of the pantograph (100)

Methodology Applied
Scientific EffectLIDAR: LIDAR

Data Source

PatentEP3295158B1System and method for the video inspection of a pantograph along an overhead contact line
Publication Date: 2020.04.08 CAMLIN ITALY SRL
  • EP3295158B1 patent drawingFigure 1
  • EP3295158B1 patent drawingFigure 2
  • EP3295158B1 patent drawingFigure 3

AI summary

Method for the video inspection of a pantograph (100) along an overhead contact line, comprising the steps of: detecting passage of the pantograph (100) in a plurality of monitoring stations (2); in each monitoring station (2), in response to the detection of the passage of the pantograph (100), illuminating a first overhead zone in which a portion of the pantograph (100) passes; in each monitoring station (2), during the step of illuminating the first overhead zone, acquiring images of the first overhead zone by means of at least one pair of stereo video cameras (5a, 5b); calculating the disparity between the images acquired; reconstructing a three-dimensional model of the portion of the pantograph (100).