Automated inspection of steel structures using magnetic climbing robots can reduce costs and improve safety, but many such structures feature interior corners that are challenging for wheeled or tracked robots to traverse. We present the first magnetic-wheeled robot to use X-ray fluorescence for steel structure inspection, Sally, capable of overcoming all interior corner transition types, traversing small obstacles, and maneuvering in tight spaces. By re-purposing its steering and sensor deployment mechanisms, the robot is able to transition back and forth between a steel wall and an adjacent steel ceiling, steel wall, or any floor. We analyze the feasibility of these interior corner transitions and validate the results through experimental demonstrations with Sally. We also demonstrate line scanning, a continuous surface measurement technique enabled by the wheeled design that estimates the average element concentrations along a line, and show it provides greater accuracy and efficiency in both simulation and robot trials compared to the traditional grid point measurement method. Finally, we discuss lessons learned from a field test of Sally at an industrial site.

Associated Video: https://youtu.be/0_AD8SDj1gc