Rail Surface Roughness Measurement Using Cantilever Acceleration Sensor

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Solution Overview

Problem

Existing rail surface roughness measurement technologies face challenges in accurately measuring surface roughness while moving along the rail due to noise and errors caused by vertical vibrations, which affect the reliability and accuracy of the measurement results.

Innovation Solution

An apparatus featuring a cantilever beam with an acceleration sensor and displacement sensors that measure vertical acceleration and displacement, respectively, while moving along the rail, allowing for the filtering of noise signals and providing accurate surface roughness measurements by adjusting the displacement sensor set's location.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the apparatus moves along the rail to measure surface roughness, then measurement coverage is improved, but measurement accuracy deteriorates due to vertical vibrations

Engineering Contradiction:
Improvemeasurement coverageVSAvoidsurface roughness measurement accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent extracts and eliminates the harmful vertical vibrations from the measurement system by using a cantilever beam configuration where the contact member touches the rail surface while the sensor remains isolated on the cantilever. This separates the measurement function from the vibration source, allowing accurate measurement while maintaining mobility along the rail.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cantilever beam acts as an intermediary element between the contact member and the acceleration sensor. It transmits the vertical displacement information from the rail surface to the sensor while isolating the sensor from the harmful vibrations generated during apparatus movement, thus enabling accurate measurement during motion.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple displacement sensors are used to improve measurement accuracy, then measurement reliability is improved, but device complexity increases

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the displacement sensor set adjustable and rotatable, allowing the same sensor assembly to serve multiple measurement locations and orientations. This multi-functional design enables reliable measurements at various rail positions without proportionally increasing device complexity, as one sensor set can be repositioned to perform multiple measurement tasks.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If the displacement sensor set location is made adjustable to measure various locations, then measurement versatility is improved, but device complexity increases

Engineering Contradiction:
Improvemeasurement location flexibilityVSAvoidsensor positioning complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transforms the static sensor positioning into a dynamic, adjustable system. The displacement sensor set can be rotated and repositioned along the rail, allowing the measurement system to adapt to various measurement locations and orientations. This dynamic positioning capability provides measurement versatility without requiring multiple fixed sensor assemblies.

Inventive Principle:
Principle #15Dynamics

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

The apparatus enables precise and reliable measurement of rail surface roughness by filtering out irrelevant vibrations, enhancing the accuracy and reliability of the measurement results, and allowing for vertical displacement measurement at various locations.

Implementation Method 1

an acceleration sensor provided at the movable end of the cantilever beam at a location opposite to the contact member to measure vertical acceleration based on a vertical displacement of the contact member

Methodology Applied
Scientific EffectAcceleration sensor measurement: Accelerometer

Implementation Method 2

a displacement sensor configured to have a lower end which contacts the top surface of the rail to measure vertical displacement caused by the unevenness of the surface of the rail

Methodology Applied
Scientific EffectDisplacement sensor measurement: Displacement

Data Source

PatentEP3256812B1Apparatus for measuring surface roughness of rail using acceleration sensor and displacement sensor
Publication Date: 2019.10.16 KOREA RAILROAD RESEARCH INSTITUTE
  • EP3256812B1 patent drawingFigure 1
  • EP3256812B1 patent drawingFigure 2
  • EP3256812B1 patent drawingFigure 3

AI summary

Provided is an apparatus for measuring surface roughness of a rail while moving along, which may measure accurate surface roughness of the rail without any noise or error generated during the movement of the apparatus by using an acceleration sensor installed in a cantilever manner, and also may ensure more excellent accuracy and reliability of the measured surface roughness of the rail by using a plurality of displacement sensors whose locations may be adjusted.