Pantograph Displacement Measurement Using Area Sensor Camera

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Solution Overview

Problem

Existing pantograph displacement measuring devices using line sensor cameras can only measure positional deviations at a single point, requiring multiple cameras to accurately measure acceleration fluctuations, leading to increased device size and cost.

Innovation Solution

A pantograph displacement measuring device utilizing a single area sensor camera and a line sensor camera, along with markers and image processing, to capture and analyze images, allowing for high-accuracy displacement measurement with a simple structure, including the use of ranging sensors and area sensor cameras to measure overhead-wire positional deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple line sensor cameras are used to measure positional deviations at multiple points, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvepositional deviation measurement accuracyVSAvoidnumber of cameras required
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from using multiple line sensor cameras (one-dimensional measurement points) to using a single area sensor camera that captures two-dimensional images. This dimensional change allows simultaneous measurement of positional deviations at multiple points across the pantograph cross-section, resolving the contradiction between measurement precision and device complexity

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

Solution Approach 2:

The patent creates a virtual model of the pantograph cross-section by capturing images at multiple positions with the area sensor camera and synthesizing a comprehensive displacement profile. This copying approach allows accurate reconstruction of the entire pantograph shape without physically placing multiple cameras at each measurement point

Inventive Principle:
Principle #26Copying

2Device complexity

If a single area sensor camera is used to capture images at multiple positions, then device complexity is reduced, but measurement precision may be compromised

Engineering Contradiction:
Improvenumber of cameras requiredVSAvoidpositional deviation measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements continuous image capture at multiple positions along the pantograph using the single area sensor camera. By continuously acquiring images at different cross-sectional positions and synthesizing them, the system maintains high measurement precision while using simplified single-camera hardware

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent divides the pantograph measurement task into multiple discrete image capture positions. The area sensor camera captures images at several cross-sectional positions, and the processing computer segments and analyzes each position's data to reconstruct the complete displacement profile, ensuring measurement precision through systematic segmentation

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 measurement of pantograph displacement and detection of trolley-wire hard spots with high precision and reduced costs, using a single area sensor camera to cover multiple locations, enhancing the detection accuracy and convenience for both maintenance and commercial vehicle applications.

Implementation Method 1

images of a pantograph to which markers for measuring hard spots have been affixed, captured by a line sensor camera

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

the use of ranging sensors and area sensor cameras to measure overhead-wire positional deviations

Methodology Applied
Scientific EffectLight time of flight: Time of Flight

Data Source

PatentEP3936369B1Pantograph displacement measuring device, and trolley-wire hard-spot detection method
Publication Date: 2023.06.21 MEIDENSHA CORP
  • EP3936369B1 patent drawingFigure 1~2
  • EP3936369B1 patent drawingFigure 3
  • EP3936369B1 patent drawingFigure 4

AI summary

[Problem] A configuration provided with: a plurality of markers 5 affixed, so as to be spaced apart in a vehicle width direction, to an end surface of a pantograph 1a; an area sensor camera 2 that is provided on a roof of a vehicle 1 and that captures an image of the plurality of markers 5; a line sensor camera 3 that is provided on the roof of the vehicle 1 and that captures an image of an overhead wire 7; and an operation processing unit 6A that determines a height-direction displacement of the pantograph 1a corresponding to a deviation position of the overhead wire 7 by extracting respective vertical lines in which the respective markers 5 appear from the image captured by the area sensor camera 2, respectively preparing marker images 9 formed by arranging each of the lines in rows, preparing reference templates 10 for single lines of the respective markers 5 based on the marker images 9, and using the respective reference templates 10 to perform pattern matching with an input image captured by the area sensor camera 2 while the vehicle 1 is traveling.