Trout-like multifunctional piezoelectric robotic fish and energy harvester
Trout-like multifunctional piezoelectric robotic fish and energy harvester
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DOI：
10.1088/1748-3190/ac011e
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发表时间：
2021-07-01
影响因子：
3.4
通讯作者：
Erturk, Alper
中科院分区：
文献类型：
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作者：
Tan, David;Wang, Yu-Cheng;Erturk, Alper
这项工作展示了我们对受鳟鱼启发的多功能机器鱼作为水下游泳者和能量采集器的实验研究。具有叉指电极的基于纤维的柔性压电复合材料，特别是粗纤维复合材料（MFC）结构，在变形和驱动力能力之间取得平衡，以产生流体动力推进力，而不需要额外的运动放大机制。一对 MFC 层压板支撑着被动鳍，当异相驱动时，它们的作用就像人造肌肉一样，在每一侧膨胀和收缩以产生弯曲。这项工作中探索的类似鳟鱼的机器鱼设计在静止水箱中进行无约束游泳和在水隧道中强加水流下进行测试，以估计最大游泳速度，超过 0.25 m s(-1)，即每秒 0.8 个身体长度。还在静态水环境中进行了水动力推力表征，结果表明鳍可以轻松产生数十 mN 的推力，类似于具有可比游泳速度的生物对应物。总体而言，这里介绍的原型产生的推力水平高于其他基于智能材料的概念（例如基于软聚合物材料的执行器，可提供大变形但较小的力），同时提供简单的设计、几何可扩展性和安静的操作，这与基于电机的机器鱼（通常使用笨重的执行器和复杂的机构）不同。此外，还进行了能量收集实验，以转换水隧道中圆柱形钝体（针对不同直径）的尾流引起的流动振动。一组钝体直径的流涡频率范围覆盖了尾部的第一振动模式，在流速约为 0.3 m s(-1) 且钝体直径为 28.6 mm 的情况下，共振时产生的平均电功率为 120 μW。这种低功耗电力可以在生态监测等场景中为机器鱼的小型传感器供电。
This work presents our experimental studies on a trout-inspired multifunctional robotic fish as an underwater swimmer and energy harvester. Fiber-based flexible piezoelectric composites with interdigitated electrodes, specifically macro-fiber composite (MFC) structures, strike a balance between the deformation and actuation force capabilities to generate hydrodynamic propulsion without requiring additional mechanisms for motion amplification. A pair of MFC laminates bracketing a passive fin functions like artificial muscle when driven out of phase to expand and contract on each side to create bending. The trout-like robotic fish design explored in this work was tested for both unconstrained swimming in a quiescent water tank and under imposed flow in a water tunnel to estimate the maximum swimming speed, which exceeded 0.25 m s(-1), i.e., 0.8 body lengths per second. Hydrodynamic thrust characterization was also performed in a quiescent water setting, revealing that the fin can easily produce tens of mN of thrust, similar to its biological counterpart for comparable swimming speeds. Overall, the prototype presented here generates thrust levels higher than other smart material-based concepts (such as soft polymeric material-based actuators which provide large deformation but low force), while offering simple design, geometric scalability, and silent operation unlike motor-based robotic fish (which often use bulky actuators and complex mechanisms). Additionally, energy harvesting experiments were performed to convert flow-induced vibrations in the wake of a cylindrical bluff body (for different diameters) in a water tunnel. The shed vortex frequency range for a set of bluff body diameters covered the first vibration mode of the tail, yielding an average electrical power of 120 mu W at resonance for a flow speed around 0.3 m s(-1) and a bluff body diameter of 28.6 mm. Such low-power electricity can find applications to power small sensors of the robotic fish in scenarios such as ecological monitoring, among others.