CAREER: Understanding the Exceptional Near-Field Auditory System of the Aye-Aye, One of the Most Unusual Primates in the World

在过去的5000万年里，眼睛的近场听觉系统，世界上最独特和濒危的灵长类动物之一，已经进化出一种特殊的觅食行为，叫做轻拍扫描。当它沿着树的表面移动时，它用它不寻常的中指轻拍木头，同时保持鼻子靠近树的表面，它的大耳朵向前弯曲，以探测树皮深处的洞，里面有它们吃的虫子。这种行为与无损检测（NDE）非常相似，无损检测是一种产生有源声波的过程，材料的响应（如回声）用于表征材料特性以及检测和评估缺陷（如空腔）。aye-aye的轻拍扫描行为是独一无二的，这使得它对于创造新的濒死体验技术特别有价值。教师早期职业发展（Career）研究的主要目标是了解眼睛独特的基于近场声学的传感和检测能力，激发新的濒死体验方法的创造。这笔拨款将帮助支持研究，为开发生物启发的濒死方法提供基础，既促进科学发展，又确保我国老化基础设施的安全。需要可靠的无损检测方法来检查老化结构，如桥梁、管道、发电厂和飞机，以及为复杂的制造部件提供质量控制评估。因此，这项研究将有利于美国经济，并通过避免关键老化基础设施的灾难性故障来促进美国社会的安全。本研究的主要假设是，眼猴特殊的近场听觉系统是由两种奇妙的适应造成的：(1)眼猴的耳部、耳道和头部的形状和形态适应了，以增强噪音的减少和对敲击反射声音的接收，并增加了近场声束的分辨率；(2)眼猴中指的形态特征适应了，以在敲击扫描过程中提供独特的声音线索。为了验证这些假设，研究小组将进行仿生和数值研究。首先，一个机器人平台将被用来模仿在轻拍扫描时的中指。实验将评估耳廓、耳头和耳道在增强耳廓声近场感知中的作用。其次，利用有限元模型对兔耳听觉系统的声场进行数值分析。最后，将设计和制造一种生物启发的轻拍扫描仪，用于检查复合材料。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Over the past 50 million years, the near-field auditory system of aye-ayes, one of the most unique and endangered primates in the world, has evolved to perform an exceptional foraging behavior called tap-scanning. As the aye-aye moves along the surface of a tree, it taps the wood with its unusual middle finger while keeping its nose near the tree’s surface and its large ears bent forward to detect deep cavities in tree bark that contains the worms they eat. This behavior is very similar to what is done in nondestructive evaluation (NDE), a process where an active acoustic wave is generated and the response from a material (e.g., echo) is used to characterize material properties as well as to detect and evaluate defects (e.g., cavities). The aye-aye’s tap-scanning behavior is unique, making it particularly valuable for creating new NDE technologies. The main goal of Faculty Early Career Development (CAREER) research is to understand the exceptional near-field acoustic-based sensing and detection capabilities of aye-ayes, inspiring the creation of new NDE methods. This grant will help support research that will provide a foundation for developing bio-inspired NDE methods, both promoting science and ensuring the safety of our nation’s aging infrastructures. Reliable NDE methods are needed to inspect aging structures, such as bridges, pipelines, power plants, and aircrafts, as well as provide quality control assessments for complex manufactured components. Therefore, this research will benefit both the U.S. economy and promoting the safety of U.S. society by circumventing catastrophic failures of critical aging infrastructures. The principal hypothesis of this research is that the exceptional near-field auditory system of aye-ayes has resulted from two marvelous adaptations: (i) shape and morphology of the aye-aye’s pinnae, ear canals, and head have adapted to enhance the noise reduction and reception of sound reflected from tapping and increase the near-field acoustic beam resolution and (ii) morphological features of the aye-aye’s middle finger have adapted to provide unique acoustic cues during tap-scanning. To test these hypotheses, the research team will perform bio-mimetic and numerical studies. First, a robotic platform will be used to mimic the aye-aye’s middle finger during tap-scanning. The effects of the pinna, head, and ear canal in enhancing the aye-aye’s acoustic near-field sensing will be evaluated experimentally. Second, finite element models will be used to numerically analyze the acoustic field of the aye-aye’s auditory system. Finally, a bio-inspired tap-scanner will be designed and manufactured to be used to inspect composite materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.