Thesis
Guided wave echolocation for inspection robots
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2025
- Thesis identifier
- T17319
- Person Identifier (Local)
- 201970413
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Industrial assets such as storage tanks and pressure vessels require routine inspections to maintain safety standards. The precise localisation of inspection points is critical for tracking structural integrity over time and ensuring systematic analysis of inspection data. These assets are typically constructed from plate-like structures welded together, making welds very common across these structure. The welded sections can be utilised as landmarks to position and localise a mobile robotic inspection system by using ultrasonic guided waves, which have been shown to reflect from welded sections and edges. This study explored the efficacy of guided waves for echolocation-based localisation of mobile robotic inspection systems using wave reflections from welded sections. A study on wave mode weld reflectivity was carried out to identify the best mode to reflect from welded sections in order to accurately range, as different modes interact with welds in different ways due to variations in wave characteristics such as energy density distribution and mode conversion effects. Through a systematic evaluation of five guided wave modes, the study identified SH1 at a frequency-thickness product of 2 MHz.mm as the most effective wave mode for robust weld reflections. SH1 consistently exhibited the highest reflection coefficient in simulation and experiment, averaging 0.45 across multiple weld geometries, with minimal mode conversion. A positional error of 2.65% was found in experiment using SH1. To maximise the efficiency of guided wave generation and reception, a novel methodology for optimising Lorentz force PCB racetrack coil Periodic Permanent Magnet (PPM) Electromagnetic Acoustic Transducers (EMATs) was developed. This optimisation methodology was found to double signal amplitude when compared to a non-optimised version of the same transducer. Following this the sensor optimisation methodology was applied to a sensor setup optimised for guided wave ranging from a mobile robot. The optimised sensor setup utilises a unidirectional side-shifted PPM array EMAT for transmission and reduced sized receiver for reception, reducing operational complexity, sensor size and magnetic holding force, and eliminating the need for an additional receiver. The experimental validation demonstrates that the optimised EMAT system significantly improves localisation accuracy while maintaining a compact and mobile-friendly form factor.
- Advisor / supervisor
- Tabatabaeipour, Morteza
- Dobie, Gordon
- Resource Type
- DOI
Relations
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PDF of Thesis T17319 | 2025-06-03 | Public | Download |