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，世界上最独特、最濒危的灵长类动物之一，指狐猴的近场听觉系统已经进化出一种特殊的觅食行为，称为敲击扫描。 当指狐猴沿着树的表面移动时，它会用它不同寻常的中指轻敲木头，同时保持鼻子靠近树的表面，它的大耳朵向前弯曲，以探测树皮上的深洞，那里有它们吃的蠕虫。这种行为非常类似于在无损评估（NDE）中所做的，无损评估是一种产生主动声波的过程，并且来自材料（例如，回声）用于表征材料特性以及检测和评估缺陷（例如，腔）。指狐猴的敲击扫描行为是独一无二的，这使得它对创造新的无损检测技术特别有价值。教师早期职业发展（CAREER）研究的主要目标是了解指猴特殊的近场声学传感和检测能力，激发新的NDE方法的创建。这笔赠款将有助于支持研究，这将为开发生物启发的NDE方法提供基础，既促进科学，又确保我们国家老化基础设施的安全。需要可靠的无损检测方法来检测老化结构，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，并通过规避关键老化基础设施的灾难性故障来促进美国社会的安全。这项研究的主要假设是，指狐猴特殊的近场听觉系统是由两种奇妙的适应性造成的：（i）指狐猴耳廓、耳道、和头部已经适于增强噪声降低和从敲击反射的声音的接收，并且增加近场声束分辨率，以及（ii）声束的形态特征，aye的中指已经适应于在敲击扫描期间提供独特的声学提示。为了验证这些假设，研究小组将进行生物模拟和数值研究。首先，一个机器人平台将被用来模仿指狐猴的中指在点击扫描。耳廓，头部和耳道在增强指猴的声学近场传感的影响将进行实验评估。其次，将利用有限元素模型来数值分析指狐猴听觉系统的声场。最后，将设计和制造一种生物启发的敲击扫描仪，用于检测复合材料。该奖项反映了NSF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.