A Magnetic-Wheeled Inspection Robot for Interior Corner Traversal
Paul Nadan, Jai Kumar, Nate Klein, Jesse Wallace, Hairong Wang, Alexander Hakim, Adam Dassey, Thomas Hoelen, Gregory V. Lowry, Aaron M. Johnson
AI summary
Problem
Automated magnetic climbing robots struggle to traverse interior corners and small obstacles on steel structures, while traditional grid-point sampling methods are inefficient and less accurate for elemental analysis.
Approach
The authors designed Sally, a magnetic-wheeled robot that repurposes its steering and sensor deployment mechanisms to overcome magnetic adhesion during corner transitions, and validated its mobility and a novel line-scanning sampling method through simulation, lab, and field trials.
Key results
- First magnetic-wheeled robot to integrate a pXRF sensor for steel inspection
- Achieved all 90° interior corner transitions by repurposing steering and sensor deployment mechanisms
- Demonstrated line scanning that outperforms traditional grid-point measurement in accuracy and efficiency
- Validated mobility and sampling methods across controlled lab, simulation, and industrial field trials
Why it matters
Enables safer, cost-effective automated inspection of confined steel infrastructure like tanks and ship hulls, reducing reliance on hazardous manual climbing.
Abstract
Automated inspection of steel structures using magnetic climbing robots can reduce costs and improve safety, but many such structures feature interior corners that are chal- lenging 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.