Strategies for guided acoustic wave inspection using mobile robots

Abstract

Continuous non-destructive monitoring of large-scale structures 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 localized 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 localization 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? We explore this problem with Monte Carlo simulations that reveal the compromise between number of robots and performance in terms of defect location accuracy. In an experimental validation example on an aluminium plate, we show that six measurements arranged in a pentagon with a central measurement point leads to localization errors of similar magnitude to the uncertainty in sensor location.

Autonomous control for miniaturized mobile robots in unknown pipe networks

“…The proposed controller has overcome critical challenges caused by the design trade-offs and sacrifices required to keep the robot small (discussed in section 2.3 ) and controlled the robot stably, autonomously fulfilling Task 1 ( Section 2.2 ): to control the robot movement autonomously in sewer pipes, exhaustively explore a real pipe network in laboratory settings, and avoid obstacles. In this way, the proposed control architecture separates mobility, stability and navigational tasks (all of which can be implemented with only low-cost components and low power consumption) from localization, mapping and pipe inspection tasks (that may require additional, possibly more power-hungry sensors ( Worley et al, 2020 ; Aitken et al, 2021 ; Yu et al, 2021a ; Yu et al, 2021b ; Prisutova et al, 2022 ; Zhang et al, 2022 )). An example of a hybrid experiment is presented by Li et al ( Li et al, 2022 ) in this issue.…”

Ultrasonic imaging in highly heterogeneous backgrounds

“…Recent developments in sensing technology have resulted in a suite of imaging solutions germane to complex environments [13][14][15][16][17][18][19][20]. State-of-the-art examples include: penetratingradar techniques [13], infrared thermography [14], laser shearography [15], X-ray computed tomography [16], acoustic tomography [17], ultrasonic surface wave methods [18], nonlinear ultrasound [19] and laser ultrasonic imaging [20]. Among which, ultrasonic sensing often emerges as the preferred (or the only feasible) imaging modality in many applications.…”

Bio-Inspired Autonomous Navigation and Formation Controller for Differential Mobile Robots

“…Other applications for multi-agent systems and social robots navigation, such as delivery robots, warehouses, indoor service robots, surveillance robots, etc., are listed in [ 7 ]. An interesting application is presented in [ 8 ], where a multi-robot system is proposed for defect detection and location on large surface metal plates; it is pointed out that there are several trade-offs between the performance in terms of defect location accuracy and the number of robots, their navigation capabilities, and ability to keep a formation.…”