FROMLINE: Laura Thomas
Newswise – An inspection design method and procedure that allows mobile robots to inspect large pipe structures has been demonstrated with the successful inspection of multiple defects on a three-meter-long steel pipe using guided acoustic wave sensors.
The University of Bristol team, led by Professor Bruce Drinkwater and Professor Anthony Croxford, developed an approach to inspect a long steel pipe with multiple defects, including circular holes of different sizes, a crack-like defect and pits, via a designed inspection path to achieve a 100% to achieve sufficient detection coverage for a defined reference error.
In the study, published today in NDT and E International, they show how they were able to effectively study large plate-like structures using a network of independent robots, each carrying sensors capable of both sending and receiving guided acoustic waves. Echo mode.
This approach has the great advantage of minimizing communication between robots, not requiring synchronization and increasing the possibility of on-board processing to reduce data transmission costs and therefore reduce the overall cost of inspection. The inspection was divided into a defect detection and a defect localization phase.
Lead author Dr. Jie Zhang explained: “There are many robotic systems with integrated ultrasonic sensors that are used to automatically inspect pipelines from the inside, so that the pipeline operator can carry out necessary inspections without stopping the flow of products in the pipeline.” However, the available systems have difficulties , to cope with different pipe cross-sections or the complexity of the network, which inevitably leads to disruption of the pipelines during inspection. This makes them suitable for specific inspections of high-value assets such as oil and gas pipelines, but is not generally applicable.
“As the cost of mobile robots has fallen in recent years, it is increasingly possible to use multiple robots for large-scale inspection. We assume the existence of small inspection robots and investigate how they can be used for generic monitoring of a structure. This requires inspection strategies, methods and evaluation procedures that can be integrated into the mobile robots to enable accurate defect detection and localization that is cost-effective and efficient.
“We investigate this problem by considering a network of robots, each of which has a single omnidirectionally guided sound wave transducer. This configuration is considered to be probably the simplest with good potential for integration into a cost-effective platform.”
The methods used are generally applicable to other related scenarios and enable rapid quantification of the impact of decisions on detection or localization methods. The methods could be used with other materials, pipe geometries, noise levels or guided wave modes, allowing the full range of sensor performance parameters, defect sizes and types, and operating modalities to be investigated. Additionally, the techniques can be used to evaluate detection and localization performance for specific inspection parameters, for example to predict the minimum detectable error given a given detection probability and false alarm probability.
The team will now explore opportunities to collaborate with industry to further develop current prototypes for actual pipe inspections. This work is funded by the UK Engineering and Physical Sciences Research Council (EPSRC) as part of the Pipebots project.
“Pipe Inspection Using Guided Acoustic Wave Sensors Integrated into Mobile Robots” by Jie Zhang, Xudong Niu, Anthony J. Croxford, and Bruce W. Drinkwater in NDT and E International.