The unavoidable increase in train speed and load, as well as the aging of railway facilities, is requiring more and more attention to rail defects detection. As a promising tool for rail, in-service high-speed inspection, guided wave–based detection technologies have been developed in succession by researches in the past two decades. However, there is a lack of a systematic review on the developments and performances of these technologies. This article reviews ultrasonic rail inspection methods comprehensively with the focus on the state-of-the-art technologies based on guided wave. Different excitation options, including train wheel, electromagnetic acoustic transducer, pulsed laser, air-coupled, and contact piezoelectric transducer, are described, respectively, along with their inspection sensitivities, regions, and potential speeds. Finally, future challenges and prospects are discussed to a certain extent to provide references for researchers in this area.

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With the rapid growth of robot technology, robotic tiling to replace manual work gains increasing attention. However, existing studies may have oversimplified their working conditions in automatic tiling work, where the floor-tiling robot can only tile the middle area in a room, leaving the edge area to be tiled manually. This research aims to provide a vision-based solution for floor-tiling robots to determine the profile of the edge areas, aiming to improve the automation level of the tiling robot.