Eddy Current Probe Manipulation for Turbine Surface Inspection

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Solution Overview

Problem

Inspection of components within gas turbine engines, particularly for detecting small defects like cracks, is complicated due to their inaccessible locations and complex geometries, leading to costly and time-consuming dismantling and potential damage during traditional visual and borescope inspections, with limitations in detecting sub-surface defects.

Innovation Solution

An inspection system utilizing a macromanipulator with a micromanipulator, including a scotch yoke mechanism and eddy current probe, allows for precise, systematic inspection of confined spaces by separating movements and providing fine-scale reciprocating linear actuation, enabling detection of small defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If visual inspection using borescope is performed, then inspection can be conducted without dismantling, but detection of small defects and sub-surface defects is difficult

Engineering Contradiction:
Improveinspection accessibilityVSAvoiddefect detection capability
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces optical-based visual inspection with electromagnetic field-based eddy current inspection. The eddy current probe uses electromagnetic fields to induce currents in the conductive component surface, allowing detection of both surface and sub-surface defects without physical contact or dismantling, thus maintaining ease of operation while significantly improving measurement precision for small and subsurface defects

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

Solution Approach 2:

The patent changes the inspection parameter from optical reflection/transmission to electromagnetic field penetration. By using eddy current technology, the inspection system can detect defects at different depths (surface and sub-surface) by adjusting inspection parameters, thereby improving defect detection capability while maintaining non-contact inspection accessibility

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If engine dismantling is performed for inspection, then thorough inspection of inaccessible components is possible, but the operation is costly and time-consuming

Engineering Contradiction:
Improveinspection thoroughnessVSAvoiddismantling time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces mechanical dismantling with electromagnetic field-based non-contact inspection. The eddy current probe can penetrate through and inspect components internally without physical access, eliminating the need for time-consuming dismantling operations while maintaining thorough inspection capability through electromagnetic field penetration

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

Solution Approach 2:

The patent introduces electromagnetic fields as an intermediary medium to transmit inspection information. Instead of physically accessing components through dismantling, the eddy current probe uses electromagnetic fields as a mediator to detect defects deep within the engine interior, thereby reducing time loss while maintaining inspection thoroughness

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If engine dismantling and rebuilding is performed, then inspection and maintenance is achieved, but potential damage to components occurs

Engineering Contradiction:
Improvecomponent integrityVSAvoiddamage during dismantling
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical contact-based inspection with non-contact electromagnetic field inspection. The eddy current probe detects defects through electromagnetic field interaction without physical contact, thereby eliminating mechanical damage to components during inspection while maintaining reliability through thorough defect detection

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

Solution Approach 2:

The patent uses electromagnetic fields as an intermediary to inspect components without direct mechanical contact. This intermediary approach allows defect detection while preventing damage to components during the inspection process, thereby protecting component integrity while maintaining inspection reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If eddy current inspection is used to detect small defects, then detection capability is improved, but fine manipulation inside the engine is required

Engineering Contradiction:
Improvesmall defect detectionVSAvoidmanipulation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the inspection system into a macromanipulator for coarse positioning and a micromanipulator for fine positioning. The macromanipulator moves the inspection end to the target area, while the micromanipulator with scotch yoke mechanism provides precise reciprocating linear actuation of the eddy current probe, thereby achieving small defect detection without requiring complex manual manipulation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic reciprocating linear actuation through the scotch yoke mechanism. The actuating arm rotates to drive the probe support back and forth along guide rails, creating controlled reciprocating motion of the eddy current probe. This dynamic mechanism enables fine manipulation for small defect detection while automating the complex positioning tasks

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 system enables accurate and efficient detection of small defects within gas turbine engines without dismantling, reducing costs and minimizing damage, while providing a digital representation for defect localization.

Implementation Method 1

eddy currents (a type of electric current) are commonly used to detect small defects (e.g., cracks) at a surface and a sub-surface level

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 2

The scotch yoke mechanism is configured to translate the probe support in response to the rotation of the actuating arm such that the probe support slides along the pair of guide rails

Methodology Applied
Scientific EffectMechanical transmission: Mechanical Advantage

Implementation Method 3

The actuating mechanism includes a magnet fixedly coupled to the actuating arm. The actuating mechanism further includes an actuating coil disposed around the housing. The actuating coil is configured to electromagnetically rotate the magnet and the actuating arm relative to the housing in response to the actuating current

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnetic Induction

Data Source

PatentEP4660624A1Inspection system and method for inspecting a surface
Publication Date: 2025.12.10 ROLLS ROYCE PLC
  • EP4660624A1 patent drawingFigure 1
  • EP4660624A1 patent drawingFigure 2
  • EP4660624A1 patent drawingFigure 3A

AI summary

An inspection system (100) for inspecting a surface (102) includes a macromanipulator (104) including an inspection end (106) configured to be disposed proximal to the surface (102). The inspection system (100) further includes a micromanipulator (108) coupled to the inspection end (106). The. micromanipulator (108) includes a housing (110), a pair of guide rails (112) at least partially disposed within and fixedly coupled to the housing (110), a probe support (114) slidably coupled to the pair of guide rails (112), an actuating arm (116) disposed within the housing (110) and coupled to the probe support (114) via a scotch yoke mechanism (118), and an actuating mechanism (120) configured to rotate the actuating arm (116) relative to the housing (110). The inspection system (100) further includes a probe (122) coupled to the probe support (114) for inspecting the surface (102).