Miranda Alvin, Hook Joshua Vander, Schaal Christoph
Department of Mechanical Engineering, California State University, Northridge, CA, USA.
Maritime and Multi-Agent Autonomy Group, Jet Propulsion Laboratory, Pasadena, CA, USA.
Ultrasonics. 2021 Feb;110:106282. doi: 10.1016/j.ultras.2020.106282. Epub 2020 Oct 25.
Substantial improvements in material processing and manufacturing techniques in recent years necessitate the introduction of effective and efficient nondestructive testing (NDT) methods that can seamlessly integrate into day-to-day aircraft and aerospace operations. Lamb wave-based methods have been identified as one of the most promising candidates for the inspection of large-scale structures. At the same time, there is presently a high level of research in the field of autonomous mobile robotics, especially in simultaneous localization and mapping (SLAM). Thus, this paper investigates a means to automate Lamb wave-based NDT by positioning sensors along a planar structure through mobile service robots. To this end, a generalized method for the mapping of plate structures using scattered Lamb waves by means of frontier exploration is presented such that an autonomous SLAM-capable NDT system can become realizable. The performance of this novel Lamb wave-based frontier exploration is first evaluated in simulation. It is shown that it generally outperforms a random frontier exploration and may even perform near-optimal in the case of an isotropic, square panel. These findings are then validated in laboratory experiments, confirming the general feasibility of utilizing Lamb waves for SLAM. Furthermore, the versatility of the developed methodology is successfully demonstrated on a more complexly shaped stiffened panel.
近年来，材料加工和制造技术取得了重大进展，这就需要引入有效且高效的无损检测（NDT）方法，这些方法能够无缝融入日常飞机和航空航天作业中。基于兰姆波的方法已被确定为检测大型结构最有前景的候选方法之一。与此同时，目前在自主移动机器人领域有大量研究，尤其是在同时定位与地图构建（SLAM）方面。因此，本文研究了一种通过移动服务机器人沿平面结构定位传感器来实现基于兰姆波的无损检测自动化的方法。为此，提出了一种利用前沿探索通过散射兰姆波对板结构进行映射的通用方法，以便能够实现具备自主SLAM功能的无损检测系统。首先在模拟中评估了这种基于兰姆波的新型前沿探索的性能。结果表明，它总体上优于随机前沿探索，在各向同性方形面板的情况下甚至可能接近最优性能。然后在实验室实验中验证了这些发现，证实了利用兰姆波进行SLAM的总体可行性。此外，所开发方法的通用性在形状更复杂的加劲板上得到了成功验证。
