Mobile Robotic Platform for Inspecting Aircraft Surfaces Using Lamb Waves

Abstract

Due to their unique material properties and high strength-to-weight ratios, composites are an attractive choice over traditional isotropic materials for use in aerospace. However, composite structures are susceptible to failure modes that are not readily identifiable by visual inspection. This raises concerns over maintaining flight safety throughout the life of an aircraft with high proportions of composite structure. Hence, there is a need for an autonomous method that allows for damage detection in composites while reducing inspection time and cost. This paper introduces the concept of automated nondestructive testing (NDT) using Lamb waves on a mobile robotic platform to detect structural features, such as edges and ribs, in addition to any defects. The robot is envisioned to perform simultaneous localization and mapping while performing ultrasonic NDT. Presented in this paper are the potential capabilities of a prototype mobile inspection robot as well as a novel method for Lamb wave-based edge-detection that results in the map of a flat surface. The latter approach is successfully applied to a numerical example as well as data from laboratory experiments.