蝙蝠声纳传感的动力学及耦合效应的物理机制研究

蝙蝠生物声纳传感的三个物理子系统(产生、发出和接收)一直被认为是近似静态的：超声是由固定在静态结构中的振动膜产生，并由静态的声音遮蔽板形状衍射发出和接收。我们近几年的研究结果对这些假设提出了挑战，验证了蝙蝠超声的产生、发出和接收均与动力学物理有关，因此拟提出一个新的综合的研究计划，对蝙蝠声纳传感的动力学及耦合物理机制进行研究。研究内容包括声道和鼻叶通过振动皮瓣的动力学模型、动态耦合物理效应的实验量化分析、实验室和自然生物环境中声音衍射的动态物理功能、声道，鼻叶及耳廓动态结构相互耦合并最终形成蝙蝠声纳系统感应能力的物理原理。项目基于时变声场的阵列测量、鼻叶的激光测振、超声与形变的同步记录、计算机视觉、微型CT扫描等技术，建立和分析蝙蝠声纳系统的非线性声音传播模型和动态时变3-D模型，揭示蝙蝠声纳系统在传播和接收一系列过程中的生物物理机理及耦合效应，为仿生声纳系统的研发提供坚实的理论基础。

The biosonar sensing in bats consists of three physical subsystems (sound generation, emission and reception). Until recently, all three components and their interactions have been considered to be approximately static or at least stationary. In this view, the ultrasound is generated by vibrating membranes fixed in a static structure, propagates through a static vocal tract to be finally diffracted by static shapes on emission and reception. The results of our research in recent years have challenged these assumptions by demonstrating that the coupling of ultrasound from the vocal tract to the emission baffle (noseleaf) as well as the diffraction on emission and reception are all dynamic processes. We therefore propose a new comprehensive research approach to describe the bat biosonar systems as a set of coupled dynamic physical mechanisms. This research will include the dynamic coupling of the vocal tract and the noseleaf, the physical effects of dynamic diffracting surfaces and the physical principles for integrating of these dynamic processing and achieving the sensing capabilities of the biosonar system. To this end, the project will develop methods for acquiring the time-variant geometries of the involved biological shapes in live and behaving bats using a combination of high-speed multi-camera computer vision and deformable digital shape models that incorporate measured parameters of biological tissues. These will be combined with synchronized laser vibrometry and recording of ultrasound. The ultrasound recording in particular will be extended to a an array measurement technique which will allow us to measure the time time-varying ultrasonic wavefields emitted by the bats. The coupling of a non-linear wave propagating through the vocal tract and time variant diffracting surfaces will be studied using numerical models that will be developed as an extension of our current capabilities. In combination, these methods will provide a relatively complete picture of as well as insight into the dynamic physical processes behind the unmatched sensory capabilities of bat biosonar.