Zhu J, White C, Wainwright D K, Di Santo V, Lauder G V, Bart-Smith H
Bio-Inspired Engineering Research Laboratory (BIERL), Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, VA 22903, USA.
Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA.
Sci Robot. 2019 Sep 18;4(34). doi: 10.1126/scirobotics.aax4615.
Tuna and related scombrid fishes are high-performance swimmers that often operate at high frequencies, especially during behaviors such as escaping from predators or catching prey. This contrasts with most fish-like robotic systems that typically operate at low frequencies (< 2 hertz). To explore the high-frequency fish swimming performance space, we designed and tested a new platform based on yellowfin tuna () and Atlantic mackerel (). Body kinematics, speed, and power were measured at increasing tail beat frequencies to quantify swimming performance and to study flow fields generated by the tail. Experimental analyses of freely swimming tuna and mackerel allow comparison with the tuna-like robotic system. The Tunabot (255 millimeters long) can achieve a maximum tail beat frequency of 15 hertz, which corresponds to a swimming speed of 4.0 body lengths per second. Comparison of midline kinematics between scombrid fish and the Tunabot shows good agreement over a wide range of frequencies, with the biggest discrepancy occurring at the caudal fin, primarily due to the rigid propulsor used in the robotic model. As frequency increases, cost of transport (COT) follows a fish-like U-shaped response with a minimum at ~1.6 body lengths per second. The Tunabot has a range of ~9.1 kilometers if it swims at 0.4 meter per second or ~4.2 kilometers at 1.0 meter per second, assuming a 10-watt-hour battery pack. These results highlight the capabilities of high-frequency biological swimming and lay the foundation to explore a fish-like performance space for bio-inspired underwater vehicles.
金枪鱼及相关的鲭科鱼类是高性能游泳者，它们经常以高频游动，特别是在诸如逃避捕食者或捕食猎物等行为期间。这与大多数鱼类机器人系统形成对比，这些系统通常以低频（<2赫兹）运行。为了探索高频鱼类游泳性能空间，我们设计并测试了一个基于黄鳍金枪鱼（）和大西洋鲭鱼（）的新平台。在增加尾鳍摆动频率的情况下测量身体运动学、速度和功率，以量化游泳性能并研究尾部产生的流场。对自由游动的金枪鱼和鲭鱼进行实验分析，以便与类似金枪鱼的机器人系统进行比较。Tunabot（长255毫米）可以达到15赫兹的最大尾鳍摆动频率，这相当于每秒4.0个体长的游泳速度。鲭科鱼类和Tunabot之间的中线运动学比较表明，在很宽的频率范围内具有良好的一致性，最大差异出现在尾鳍处，主要是由于机器人模型中使用的刚性推进器。随着频率增加，运输成本（COT）呈现出类似鱼类的U形响应，在每秒约1.6个体长时达到最小值。假设电池组为10瓦时，如果Tunabot以每秒0.4米的速度游动，航程约为9.1公里；以每秒1.0米的速度游动，航程约为4.2公里。这些结果突出了高频生物游泳的能力，并为探索类似鱼类的生物启发式水下航行器性能空间奠定了基础。
