Collaborative Research: The Roles of Inter-limb Jets and Body Angles in Metachronal Paddling

合作研究：肢体间射流和身体角度在异时划桨中的作用

• 批准号: 1706007
• 负责人: Donald Webster
• 金额: $ 25万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1706007&HistoricalAwards=false
• 关键词: Collaborative; Research; Roles; Inter; limb

Commercial underwater drones typically rely on a single propeller element. If this element were to fail, then the drone would be lost. In contrast, the existence of multiple propulsion elements would permit continued use upon failure of a single propeller. Natural aquatic organisms illustrate a unique opportunity to use multiple propulsion elements to generate small-scale jets. Krill, shrimp, and crayfish, all use several pairs of limbs in highly coordinated motion to swim. The animal rhythmically oscillates its limbs from the tail-to-head at low velocity, with the timing of each pair delayed relative to its neighbors. Nature?s design uses much less energy than our engineered underwater drones. Mechanical elements, such as gears and timing belts, could be used to cost effectively mimic nature?s design. However, the underlying fluid dynamics of this metachronal (sequential) paddling is not well-understood. A limited number of studies have suggested limb morphology, the precision timing of the paddling sequence, and the generation of jets in the wake of the organism all contribute to this unique propulsion mechanism. This research project examines how coordination of adjacent limbs interact with the flow past the body to generate propulsive jets in the wake. Uncovering the underlying fluid dynamic principles of metachronal paddling will enable scalability to engineered devices, allowing for efficient design of miniaturized, bio-inspired autonomous underwater drones. This research project examines how the coordinated motion of multiple oscillating paddles merge with large-scale flow past a submerged object to generate propulsive forces. A combination of experiments with both live animals and robotic models will be used. Tomographic particle image velocimetry measurements of free-swimming aquatic organisms will be used to validate flow fields predicted by physical models. Self-propelled metachronal swimming robots will be used to examine the flow for individual and collective motion of the robots. Mechanical performance with respect to body angles, swimming speeds, and neighbor distances in individual and small groups of metachronal paddling robots will be examined. A primary project outcome will be the fluid dynamics mechanism by which aquatic organisms achieve large body speeds by paddling individual limbs at low velocity. The outcomes of this research will enable engineers to design and coordinate the motion of multiple propellers on engineered devices. In addition, the research project trains undergraduate and graduate students to conduct interdisciplinary research in bioengineering. Existing mechanisms at both institutions (NSF-funded Oklahoma Louis-Stokes Alliance for Minority Participation and Georgia Tech FOCUS program) are being used to recruit under-represented students for the project, and the researchers are participating in outreach activities to high school students and their teachers.

商用水下无人机通常依赖于单个螺旋桨元件。如果这个元件失效，那么无人机就会丢失。相比之下，多个推进元件的存在将允许在单个螺旋桨失效时继续使用。天然水生生物展示了利用多种推进元件产生小规模射流的独特机会。磷虾、虾和小龙虾都是用几对四肢高度协调地游动。这种动物以低速有节奏地从尾巴到头部摆动四肢，每对肢体的时间相对于相邻的肢体延迟。自然?我们的设计比我们设计的水下无人机消耗的能量少得多。机械元件，如齿轮和正时皮带，可以用来经济有效地模仿自然？年代的设计。然而，这种超时间（顺序）划水的潜在流体动力学尚未得到很好的理解。有限数量的研究表明，肢体形态、划水顺序的精确定时以及生物尾迹中产生的射流都有助于这种独特的推进机制。这个研究项目研究了相邻肢体的协调如何与流过身体的气流相互作用，从而在尾迹中产生推进射流。揭示超向划桨的流体动力学原理将使工程设备的可扩展性成为可能，从而实现小型化、仿生自主水下无人机的高效设计。本研究项目探讨了多个振荡桨的协调运动如何与经过水下物体的大规模流动合并以产生推进力。将使用活体动物和机器人模型的结合实验。自由游动的水生生物的层析粒子图像测速测量将用于验证由物理模型预测的流场。将使用自走式异向游泳机器人来检测机器人个体和集体运动的流量。机械性能方面的身体角度，游泳速度，和邻居的距离，在个人和小群体的超向划水机器人将被检查。一个主要的项目成果将是流体动力学机制，水生生物通过在低速下划动单个肢体来实现大的身体速度。这项研究的结果将使工程师能够在工程装置上设计和协调多个螺旋桨的运动。此外，该研究项目还培养本科生和研究生进行生物工程跨学科研究的能力。这两个机构的现有机制（美国国家科学基金会资助的俄克拉何马州路易斯-斯托克斯少数民族参与联盟和佐治亚理工学院的焦点项目）正在被用来招募代表性不足的学生参与该项目，研究人员正在参与向高中生和他们的老师开展的推广活动。