共查询到17条相似文献，搜索用时 406 毫秒
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仿生机器鱼作为一种高效、高机动的水下机器人,得到了科研人员的广泛关注,对BCF方式机器鱼尾鳍推进效率的研究是其中的重点方向。目前对尾鳍推进效率的优化研究,大多局限于尾鳍单一参数的优化,这与自然鱼类的游动状态相差甚远,因而不能真正达到推进效率最大化的目的。本文提出了尾鳍多参数优化方案,通过对尾鳍转动频率、摆动幅值、击水角度和摆动周期等参数的联合优化,得到一组特定游速下的参数值,结果表明本研究对象在游速0.6L m/s时(L为体长),数值计算推进效率为65.7%,仿真推进效率为64.3%的,均大于目前单一参数的优化结果,充分体现了尾鳍多参数配合的优越性。本文的研究,对提高仿生机器鱼的推进效率具有积极作用。 相似文献
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为研究鱼类高速游动机理,以金枪鱼月牙形尾鳍为对象,采用面元法计算分析了其非定常水动力性能。假设尾鳍在横移和摇摆的同时,以某一匀速向前运动,并假设其在弦向和展向以某一给定规律发生变形,以模仿柔性变形。探讨了前进速度、横移和摇摆的幅度、频率及其相位差对柔性尾鳍推进性能的影响,并与做相应运动的刚性尾鳍进行了对比。 相似文献
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摆动尾鳍水动力性能的试验和数值研究 总被引：1，自引：0，他引：1
鱼类能够在水下高速度、低噪音、高效率地游动。鱼类出色的推进性能通过其摆动尾鳍实现。这种摆动尾鳍推进方式已经用在了水下无人航行器上。因此研究摆动尾鳍的水动力性能是非常有意义的。对摆动尾鳍的推进水动力性能进行了详尽的研究。设计、装配了一套仿尾鳍推进系统,并对其进行了相应的水动力试验。在试验中研究了运动参数对摆动尾鳍水动力性能的影响。与此同时,采用基于雷诺平均N-S方程的数值方法对摆动尾鳍的水动力性能进行了研究。在数值计算中采用了k-ωSST湍流模型和有限体积法。数值计算结果和水动力试验结果进行了比较。对尾鳍表面的压力分布和流场中的尾涡结构进行了分析。水动力试验和数值计算都表明摆动尾鳍可以产生推进力和较高的推进效率。 相似文献
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作者提出鲭鱼(Scomber scombrus L.)、绿青鳕(Pollachius virens(L))和鲱鱼(Clupea harengus L.)的游泳运动学特性。实验表明,这三种鱼类的游泳速度与摆尾频率成线性关系。当泳速大于三倍体长/秒(BL/S)时,单位游距几乎不随游速变化,其平均值分别为:鲭鱼0.90体长(BL)、绿青鳕0.88BL、鲱鱼0.70BL。其摆尾幅度都不随游速变化,平均值在0.21～0.23BL之间,各种鱼之间无显著差别。作者认为,鱼类游泳的单位游距与鱼类的体型、肌肉及游泳推进性能有关,而单位游距的差异是身体—尾鳍式游泳的鱼类之间最大游速差异的主要原因。 相似文献
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控制圆柱体或翼型的行波壁会抑制大规模的分离流动,进而减少阻力。鱼类在游动过程中经常出现行波壁,而行波壁对鱼类游动性能的影响机制尚不清楚。以金枪鱼游动为基础,耦合行波壁,采用锐利界面浸没边界法(IBM)解决摆动过程带来的大变形运动边界问题。结果表明：行波壁的出现改变了金枪鱼体后涡的形成和发展,进而改变了摩擦阻力和压差阻力的分布;耦合行波壁使得摩擦阻力的波动幅值增加,压差阻力有所减小,从而降低了金枪鱼游动过程的阻力。研究的行波壁减阻机制可应用于提高仿生机器鱼的性能,随着智能材料的发展,该机制将在仿生机器鱼的研制中体现其现实意义。 相似文献
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以鱼体和鱼鳍作为研究对象,在流场中进行数值模拟分析对于研究鱼类本身游动的高速、高效的游动机理和仿生工程上的应用具有十分重要的意义。以金枪鱼为仿生对象,以目前常用的回转体型水下机器人为对比对象,在三维软件Solidworks中结合金枪鱼的运动与形体特征建立鱼体模型和回转体机器人模型,并将建立的模型转换格式后导入Fluent软件中,在来流方向设置为与模型方向相平行的流场中进行有限元数值计算。计算中物理场采用中心差分插值方法,流动模型采用RNG两方程模型,结合具体参数进行了推导计算。计算结果表明,与常用的回转体型水下机器人相比,仿金枪鱼可有效的减小其在水中航行的阻力,提高推进效率。而且,仿生机器鱼在设计中应着重于头部、尾鳍及鱼体流线型部分的设计,其中为最大程度上减小仿生机器鱼运动时的阻力,应更侧重于仿生机器鱼体的流线型外形的优化设计。数值计算结果为仿生机器鱼的结构设计提供了一个良好的力学基础,对于减小运行阻力、提高仿生机器鱼的运动控制水平具有较高的指导意义。 相似文献
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将仿生机器鱼的C-型转向机动划分为弯曲阶段、保持阶段和伸展阶段,首先基于计算流体力学（CFD）方法建立了鱼体与流体相互作用的耦合求解方法,其次通过二次开发FLUENT实现机器鱼在C-型转向机动过程中鱼体的大变形运动,最后数值计算了机器鱼在C-型转向机动过程中的运动性能、水动力性能和流场涡结构。计算结果表明：仿生机器鱼在弯曲阶段和保持阶段进行快速的转向;在伸展阶段,机器鱼的艏向角速度和侧向速度快速的减小至零值,而前进速度则快速的增加,在伸展阶段结束时获得一个较大的前进速度;在滑行阶段,仿生机器鱼以获得的纵向速度向前滑行,并且纵向速度缓慢的减小。机器鱼的C-型转向机动能够实现小范围内的大角度转向;在弯曲阶段和伸展阶段鱼体的快速弯曲和伸展运动各产生一个涡环,每个涡环产生一个射流,射流产生作用于机器鱼上的水动力和力矩。 相似文献
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温度和盐度骤变条件下凡纳滨对虾的行为变化研究 总被引：1，自引：0，他引：1
以视频记录分析的方法,研究凡纳滨对虾Litopenaeus vannamei在温度和盐度骤变条件下的运动行为、摄食行为及相关生理活动的变化。结果表明,当温度由29℃骤降至18和23℃时,对虾的活动频率、游走速度和颚舟片的摆动频率明显下降,索饵时间显著增加(p<0.05);当温度由29℃骤升至36℃时,对虾的活动频率、游走速度和颚舟片的摆动频率显著升高(p<0.05),索饵时间没有显著差异(p>0.05)。当盐度由30骤降至5和10时,对虾表现出强烈的逃避行为,活动频率、游走速度和颚舟片的摆动频率均显著升高(p<0.05),并且在观察时间内没有发生摄食行为。 相似文献
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Review of fish swimming modes for aquatic locomotion 总被引：6，自引：0，他引：6
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In the present study the effect of caudal length on hydrodynamic performance of flapping foil is investigated. According to reality of swimming of fishes, the kinematics of their oscillation tail is involved with two rotational motions where one of them causes the tail to move in circular direction and the other leads the tail to pitch around its pitch axis. With this concept, a generalized kinematic model is considered. According to simulation of the motion trajectory of flapping foil, it is shown that the length of caudal may affect the hydrodynamic performance. It is shown that at lower and higher Strouhal numbers (St < 0.2 and St > 0.6) the hydrodynamic performance of flapping foil is optimum when the length of caudal is infinitive. It should be noted that at higher caudal length the variation of propulsive efficiency and produced thrust are stopped and these hydrodynamic parameters are kept at constant values. Additionally, it is demonstrated that there is the possibility of improving propulsive efficiency at moderate Strouhal numbers (0.2 < St < 0.6) by manipulation of caudal length. Furthermore, it is shown that in some cases the manipulation of caudal length may increase thrust coefficient as the propulsive efficiency is also increased. 相似文献
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参照蝠鲼等鱼类游动方式所研制的水下仿生扑翼机器人具有效率高、机动性强、负载能力大等多方面优势。由于其广阔的应用前景,水下仿生扑翼机器人已逐步成为水下航行器领域的研究热点。本文系统地将蝠鲼的生物学特性、机器人的结构设计、动力学模型、单体运动控制、集群运动控制以及实验研究等方面的国内外研究进展进行了总结和梳理。已有的研究表明：水下仿生扑翼机器人正在朝着软体化、集群化、 高机动等方向发展,新兴的水下仿生扑翼机器人及仿生集群能够更加精确的模拟真实生物的游动姿态,并开展相关任务。当下的研究为水下仿生扑翼机器人性能的进一步优化与提升奠定了坚实的理论与实践基础。 相似文献
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The Development of a Biologically Inspired Propulsor for Unmanned Underwater Vehicles 总被引：1，自引：0，他引：1
Tangorra J.L. Davidson S.N. Hunter I.W. Madden P.G.A. Lauder G.V. Dong Haibo Bozkurttas M. Mittal R. 《Oceanic Engineering, IEEE Journal of》2007,32(3):533-550
Fish are remarkable in their ability to maneuver and to control their body position. This ability is the result of the coordinated movement of fins which extend from the body and form control surfaces that can create and vector forces in 3-D. We have embarked on a research program designed to develop a maneuvering propulsor for unmanned undersea vehicles (UUVs) that is based on the pectoral fin of the bluegill sunfish. For this, the anatomy, kinematics, and hydrodynamics of the sunfish pectoral fin were investigated experimentally and through the use of computational fluid dynamics (CFD) simulations. These studies identified that the kinematics of the sunfish pectoral fin are very complex and are not easily described by traditional ldquorowingrdquo- and ldquoflappingrdquo-type kinematics. A consequence of the complex motion is that the pectoral fin can produce forward thrust during both its outstroke (abduction) and instroke (adduction), and while doing so generates only small lateral and lift forces. The results of the biological studies were used to guide the design of robotic pectoral fins which were built as experimental devices and used to investigate the mechanisms of thrust production and control. Because of a design that was based heavily on the anatomy of the sunfish fin, the robotic pectoral fins had the level of control and degrees of freedom necessary to reproduce many of the complex fin motions used by the sunfish during steady swimming. These robotic fins are excellent experimental tools, and are an important first step towards developing propulsive devices that will give the next generation of UUVs the ability to produce and control thrust like highly maneuverable fish. 相似文献
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The energy extraction performance of a flapping foil generator is studied through experiment and numerical simulation. A practical flapping foil generator has been proposed. The heave motion and the pitch motion of the foil are adjusted through a crankshaft-like structure. The heave and pitch motions of the foil are transferred to the rotational motion of the main shaft. A pair of gears is adopted to increase the pitch angle. A prototype with pitch amplitude θ0 = 60∘ has been built and the experiment is carried out in a tunnel. The overall performance of the mechanism has been analysed. Good agreement of numerical results and experiment data has been found. Further simulations with larger pitch amplitudes are carried out. It is found that higher efficiency can be achieved with larger pitch amplitude at medium frequency. 相似文献
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鞍带石斑鱼仔稚幼鱼骨骼发育与生长特性研究 总被引：1，自引：0，他引：1
骨骼发育对于养殖鱼类苗种培育至关重要,骨骼畸形会影响仔稚幼鱼的外部形态及功能需求。作者利用骨骼染色技术和显微测量的方法对鞍带石斑鱼(Epinepheluslanceolatus)仔稚幼鱼的骨骼发育及生长特性进行连续观察和测量。实验结果表明:鞍带石斑鱼初孵仔鱼不存在骨与软骨结构,鞍带石斑鱼在变态前期和变态早期(长棘期)仔鱼的全长、颅骨长度、脊柱长度及尾鳍复合物的长度增加缓慢,骨骼发育过程中与摄食、呼吸及游泳功能相关的骨骼优先发育,如颅骨(颌骨、鳃)和鳍元件,且骨化顺序与发育顺序基本一致。进入变态晚期(收棘期),营养摄取及利用的器官发育趋于完善,稚鱼进入快速生长阶段。此外,在仔稚鱼发育早期,颅骨、脊柱以及尾鳍复合物中存在异速生长特性,呈现为在变态前期和变态早期(长棘期)颅骨和尾鳍复合物为正异速生长,而脊柱为负异速生长;在变态晚期(收棘期)和变态后期,颅骨为负异速生长,而脊柱和尾鳍复合物为近等速生长。因此,鞍带石斑鱼仔稚幼鱼的颅骨、脊柱及尾鳍复合物骨骼发育的异速生长现象与摄食、呼吸及游泳功能相适应。 相似文献
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This work develops a control system for the waypoint-tracking of a biomimetic autonomous underwater vehicle (BAUV). The BAUV swims forward by oscillating its body and caudal fin. It turns by bending its body and caudal fin toward the turning direction. The control algorithm uses the oscillating frequency to control the forward velocity, and applies a body-spline offset parameter to control the heading velocity. The motion of the BAUV is undulatory, so moving averages of swimming velocity and heading errors are used as feedback signals. The stability of the control system is discussed using a Lyapunov function. Finally, the effectiveness of the control algorithm is experimentally confirmed. 相似文献