[4C6] Strategies for pipeline inspection using mobile robots
J Zhang, X Niu, A Croxford and B Drinkwater
University of Bristol, UK
Continuous non-destructive monitoring of large-scale pipelines is extremely challenging with traditional manual inspections. In this paper, we explore possible strategies that a collection of inspection robots could adopt to address this challenge. We envision the continuous inspection of a plate performed by multiple robots or a single robot that combines measurements from multiple locations. The robots use guided ultrasonic waves to interrogate a localised region for defects such as cracking or corrosion. In the detection stage, the receiver operating characteristic defines a detection zone in which a defect is thought to be present. In the localisation stage, further measurements are made to locate the defect within this zone to a certain accuracy. We then address the question of what additional measurements are needed to achieve a given level of performance in the presence of uncertainty in robot locations? The problem is explored with Monte Carlo simulations that reveal the compromise between the number of robots and performance in terms of defect location accuracy. In an experimental validation example on a steel pipe with multiple defects, it is shown that six measurements arranged in a pentagon with a central measurement point leads to localisation errors of a similar magnitude to the uncertainty in sensor location.
