Lamb wave-based nondestructive inspection using a mobile robotic platform

摘要

Guided wave-based methods are promising for efficient, large-scale testing. However, with many nondestructive testing (NDT) techniques, the accuracy and reliability is generally dependent on the operator's conduct. To bridge this gap, a preliminary design is implemented in this work that allows a mobile robot to perform NDT. The design implements an active guided wave-based method centered around air-coupled transducers used in a pitch-catch configuration. The on-board circuitry allows the robot to either output an amplified actuation signal, or capture low-amplitude wave signals. In combination with odometry-type sensors, a map of the (unknown) structure, onto which the robot is deployed, is automatically created. During post-processing, any "hidden" structural features or defects can be identified and localized from the recorded guided wave signals. The unique combination of sensory information is demonstrated in laboratory experiments on unstiffened and stiffened aluminum plates. The feasibility of the robotic NDT, including the detection of a stiffener, is discussed by comparing the results to reference values and existing data from the literature. The results indicate that it is generally feasible to employ a mobile robotic platform to conduct guided wave-based NDT to create a map of an unknown surface.