Development of a Mobile Robot System for the Visual Inspection of Railcar Undercarriage Equipment

Abstract This study explores the design and feasibility of using a mobile robotic platform, equipped with digital cameras, thermal imaging, and similar systems for visual inspection of rolling-stock undercarriage while stationary. Condition monitoring and modern inspection methods are important parts for ensuring safe, reliable, and efficient operation of railroad equipment. Although the current wayside imaging inspection systems have proven to be effective, they are stationary and costly. The system cost, complexity, and inability to transport them to where the needs may exist have limited their widespread adaptation by the railroads. Manual train-side inspections are limited to what the train inspector can see from the side. They do not allow inspecting the undercarriage components without extending inspection time and potentially exposing personnel to safety hazards. This study presents a functional system capable of traversing over and in between the rails, as the means for cost-effective train undercarriage inspection in places such as railyards or sidings. The ability to scan railcars safely will enable detecting and documenting their condition for improved maintenance diagnostics and preventing maintenance. The results of preliminary tests with off-the-shelf cameras capable of 120 FPS recording are also included. The tests indicate that the close proximity between the cameras and the undercarriage components pose a challenge in ensuring that clear and visible images can be captured, especially when moving at higher speeds (say, more than 5 mph) and in low lighting. Traveling on ballasts and ties also poses challenges in terms of the vibrations caused by the rough terrain. The image stabilization feature that is present in most modern cameras is particularly helpful with reducing some of the blurring effects from the vibrations.