Robotic Ultrasonic Inspection of Large and Complex Structural Assets

Abstract

The implementation of robotic inspection solutions can provide massive improvements in the non-destructive testing and evaluation of large industrial structural assets. Current on-the-market remote inspection solutions are often limited in scope and lack the positional accuracy necessary for robust and repeatable structural health monitoring. This paper, therefore, describes multiple robotic navigation and inspection techniques to tackle a variety of challenges. Conventional inspection systems utilizing ultrasonic phased arrays for defect detection in large structures like storage tanks and flat steel plates typically employ a localized inspection approach. However, these systems often suffer from slow inspection speeds and an increased potential for human error, particularly in the case of large structures requiring repetitive inspections. The first challenge addressed is the inspection of large, thick steel plates used in the manufacture of industrial assets. The proposed solution focuses on achieving precise positional accuracy for spot gauge-thickness measurements and detecting laminations and inclusions. The system's novelty lies in utilizing the inspection sample itself for positional tracking. While the introduction of an automatic crawler-based approach speeds up the inspection process, it remains time-consuming and generates a substantial amount of data. To tackle this challenge, when the thickness of the inspected component allows, ultrasonic guided waves (UGW) can be employed for mid to long-range inspections. The second example outlines the integration of UGW with robotic inspection systems, which could significantly reduce inspection times by enabling rapid scanning and providing access to inaccessible regions. The final system looks at complex geometry, such as welded inserts or piping networks, and the implementation of ultrasonic phased array capabilities remotely and accurately. Standard crawlers for weld inspection are limited to simple geometry such as plates and large-bore pipes. The proposed system combines the flexibility of a sixdegree- of-freedom robotic manipulator with the remote capabilities of a magnetic base. Imbedding a sensor-driven system for live geometry assessment and tool path planning.