Department of Mechanical Engineering, Shandong University, 250100 Jinan, People's Republic of China. Department of Mechanical Engineering, Virgina Tech, Blacksburg, VA 24061, United States of America. Shandong University - Virginia Tech International Laboratory, Shandong University, 250100 Jinan, People's Republic of China.
Bioinspir Biomim. 2018 Jul 20;13(5):056003. doi: 10.1088/1748-3190/aacd5e.
The ultrasonic emission of the biosonar systems of bats, such as Old World leaf-nosed bats (family Hipposideridae) and the related horseshoe bats (family Rhinolophidae), is characterized by a unique dynamics where baffle shapes ('noseleaves') deform while diffracting the outgoing wave packets. As of now, nothing comparable to this dynamics has been used in any related engineering application (e.g. sonar or radar). Prior work with simple concave baffle shapes has demonstrated the impact of the dynamics on the emission characteristics, but it has remained unclear whether this was simply due to the change in aperture size or also influenced by the geometrical shape detail. Hence, it has also remained unclear whether it would be possible to further enhance the time-variant effects reported so far through different static and dynamic geometries. To address this issue, we have created a dynamic emission baffle with biomimetic shape detail modeled after Pratt's roundleaf bats (Hipposideros pratti). The impact of the dynamic deformation of the shape on the time-variant emission characteristics was evaluated by virtue of the gradient magnitude and the entropy in the gradient orientation. The results have shown that the dynamics results in much larger gradients in signal representation, which change jointly over direction and time.
蝙蝠的生物声纳系统的超声发射，如旧大陆叶鼻蝠（叶鼻蝠科）和相关的马蹄蝠（马蹄蝠科），其特点是独特的动态，其中挡板形状（“鼻叶”）在衍射出射波包时会变形。到目前为止，还没有任何类似的动态应用于任何相关的工程应用（例如声纳或雷达）。先前使用简单的凹面挡板形状的工作已经证明了这种动态对发射特性的影响，但仍然不清楚这是否仅仅是由于孔径大小的变化，还是也受到几何形状细节的影响。因此，也不清楚是否可以通过不同的静态和动态几何形状进一步增强迄今为止报道的时变效应。为了解决这个问题，我们创建了一个具有仿生形状细节的动态发射挡板，其形状细节是仿照普拉特圆叶蝠（ Hipposideros pratti ）建模的。通过梯度幅度和梯度方向的熵来评估形状动态变形对时变发射特性的影响。结果表明，动态产生的信号表示中的梯度大得多，并且在方向和时间上共同变化。
