Editing Fin (section)

==Robotics==
[[File:RobotFishCharlie.jpg|thumb|210px|right|In the 1990s the [[CIA]] built a robotic catfish called ''Charlie'' to test the [[Feasibility study|feasibility]] of [[unmanned underwater vehicle]]s.]]
{{externalimage
|float=center
|width=200px
|video1=[https://www.youtube.com/watch?v=lEeb72ZJKAk ''Charlie'' the catfish]  – ''CIA video''
|video2=[https://www.youtube.com/watch?v=u8tfES8gImc AquaPenguin] – ''Festo, YouTube''
|video3=[https://www.youtube.com/watch?v=-vT-oidWyXE AquaRay] – ''Festo, YouTube''
|video4=[https://www.youtube.com/watch?v=mKMN-dz8n3k AquaJelly] – ''Festo, YouTube''
|video5=[https://www.youtube.com/watch?v=TKeVVKGEDLc AiraCuda ] – ''Festo, YouTube''}}

The use of fins for [[Aquatic locomotion|the propulsion]] of aquatic animals can be remarkably effective. It has been calculated that some fish can achieve a [[Marine propulsion|propulsive]] efficiency greater than 90%.<ref name=Sfakiotakis>{{cite journal|last1=Sfakiotakis |first1=M |last2=Lane |first2=DM |last3=Davies |first3=JBC |year=1999 |title=Review of Fish Swimming Modes for Aquatic Locomotion |url=http://www.mor-fin.com/Science-related-links_files/http___www.ece.eps.hw.ac.uk_Research_oceans_people_Michael_Sfakiotakis_IEEEJOE_99.pdf |journal=IEEE Journal of Oceanic Engineering |volume=24 |issue= 2|pages=237–252 |doi=10.1109/48.757275 |url-status=dead |archive-url=https://web.archive.org/web/20131224091124/http://www.mor-fin.com/Science-related-links_files/http___www.ece.eps.hw.ac.uk_Research_oceans_people_Michael_Sfakiotakis_IEEEJOE_99.pdf |archive-date=2013-12-24 |citeseerx=10.1.1.459.8614 |bibcode=1999IJOE...24..237S |s2cid=17226211 }}</ref> Fish can accelerate and maneuver much more effectively than [[boat]]s or [[submarine]], and produce less water disturbance and noise. This has led to [[Biomimicry|biomimetic]] studies of underwater robots which attempt to emulate the locomotion of aquatic animals.<ref>{{cite web|url=http://rjmason.com/ramblings/robotFishMarket.html|author=Richard Mason|title=What is the market for robot fish?|url-status=dead|archive-url=https://web.archive.org/web/20090704021443/http://rjmason.com/ramblings/robotFishMarket.html|archive-date=2009-07-04}}</ref> An example is the Robot Tuna built by the [http://fibo.kmutt.ac.th/ Institute of Field Robotics], to analyze and mathematically model [[Fish locomotion|thunniform motion]].<ref>{{cite web|url=http://fibo.kmutt.ac.th/project/eng/current_research/fish.html|publisher=Institute of Field Robotics|title=Fish Robot|author=Witoon Juwarahawong|access-date=2007-10-25 |archive-url = https://web.archive.org/web/20071104081550/http://fibo.kmutt.ac.th/project/eng/current_research/fish.html |archive-date = 2007-11-04}}</ref> In 2005, the [[Sea Life London Aquarium]] displayed three robotic fish created by the computer science department at the [[University of Essex]]. The fish were designed to be autonomous, swimming around and avoiding obstacles like real fish. Their creator claimed that he was trying to combine "the speed of tuna, acceleration of a pike, and the navigating skills of an eel".<ref>{{cite web|url=http://cswww.essex.ac.uk/staff/hhu/HCR-Group.html#Entertainment|publisher=Human Centred Robotics Group at Essex University|title=Robotic fish powered by Gumstix PC and PIC|access-date=2007-10-25|archive-url=https://web.archive.org/web/20110814141015/http://cswww.essex.ac.uk/staff/hhu/HCR-Group.html#Entertainment|archive-date=2011-08-14|url-status=dead}}</ref><ref name="cnn">{{Cite web
|url=http://edition.cnn.com/2005/TECH/10/07/spark.fish
|title=Robotic fish make aquarium debut
|work=cnn.com
|publisher=[[CNN]]
|date=10 October 2005
|access-date=12 June 2011
|archive-date=26 November 2020
|archive-url=https://web.archive.org/web/20201126104911/http://edition.cnn.com/2005/TECH/10/07/spark.fish/
|url-status=dead
}}</ref><ref name="london_times1">{{Cite web
|url=https://www.thetimes.com/travel/destinations/uk-travel/england/london-travel/merlin-entertainments-tops-up-list-of-london-attractions-with-aquarium-buy-6tql7m9knhn
|title=Merlin Entertainments tops up list of London attractions with aquarium buy
|last=Walsh
|first=Dominic
|work=[[The Times]]
|publisher=Times of London
|date=3 May 2008
|access-date=12 June 2011
|archive-date=21 December 2016
|archive-url=https://web.archive.org/web/20161221060004/http://www.thetimes.co.uk/tto/business/industries/leisure/article2172983.ece
|url-status=live
}}</ref>

The ''AquaPenguin'', developed by [[Festo]] of Germany, copies the streamlined shape and propulsion by front flippers of [[penguin]]s.<ref>[http://www.controlengeurope.com/article/24663/For-Festo--Nature-Shows-the-Way.aspx For Festo, Nature Shows the Way] {{Webarchive|url=https://web.archive.org/web/20200928111347/https://www.controlengeurope.com/article/24663/For-Festo--Nature-Shows-the-Way.aspx |date=2020-09-28 }} ''Control Engineering'', 18 May 2009.</ref><ref>[http://www.gizmag.com/bionic-penguins-fly-through-water--and-air/11545/ Bionic penguins fly through water... and air] {{Webarchive|url=https://web.archive.org/web/20160304052906/http://www.gizmag.com/bionic-penguins-fly-through-water--and-air/11545/ |date=2016-03-04 }} ''Gizmag'', 27 April 2009.</ref> Festo also developed ''AquaRay'',<ref>[http://www.technovelgy.com/ct/science-fiction-news.asp?newsnum=2249 Festo AquaRay Robot] {{Webarchive|url=https://web.archive.org/web/20201124125555/http://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=2249 |date=2020-11-24 }} ''Technovelgy'', 20 April 2009.</ref> ''AquaJelly''<ref>[http://www.engineeringtv.com/video/The-AquaJelly-Robotic-Jellyfish The AquaJelly Robotic Jellyfish from Festo] {{Webarchive|url=https://web.archive.org/web/20150924000817/http://www.engineeringtv.com/video/The-AquaJelly-Robotic-Jellyfish |date=2015-09-24 }} ''Engineering TV'', 12 July 2012.</ref> and ''AiraCuda'',<ref>[http://www.theengineer.co.uk/in-depth/analysis/lightweight-robots-festos-flying-circus/1009421.article Lightweight robots: Festo's flying circus] {{Webarchive|url=https://web.archive.org/web/20150919071715/http://www.theengineer.co.uk/in-depth/analysis/lightweight-robots-festos-flying-circus/1009421.article |date=2015-09-19 }} ''The Engineer'', 18 July 2011.</ref> respectively emulating the locomotion of manta rays, jellyfish and barracuda.

In 2004, [[Hugh Herr]] at MIT prototyped a [[biomechatronic]] robotic fish with a living [[actuator]] by surgically transplanting muscles from frog legs to the robot and then making the robot swim by pulsing the muscle fibers with electricity.<ref>{{cite journal | last1 = Huge Herr | first1 = D. Robert G | title = A Swimming Robot Actuated by Living Muscle Tissue | journal = Journal of NeuroEngineering and Rehabilitation | volume = 1 | issue = 1| page = 6 | doi = 10.1186/1743-0003-1-6 | pmc=544953 | pmid=15679914 | date=October 2004 | doi-access = free }}</ref><ref>[http://science.howstuffworks.com/biomechatronics4.htm How Biomechatronics Works] {{Webarchive|url=https://web.archive.org/web/20201205000258/http://science.howstuffworks.com/biomechatronics4.htm |date=2020-12-05 }} ''HowStuffWorks''/ Retrieved 22 November 2012.</ref>

Robotic fish offer some research advantages, such as the ability to examine part of a fish design in isolation from the rest, and variance of a single parameter, such as flexibility or direction. Researchers can directly measure forces more easily than in live fish. "Robotic devices also facilitate three-dimensional kinematic studies and correlated hydrodynamic analyses, as the location of the locomotor surface can be known accurately. And, individual components of a natural motion (such as outstroke vs. instroke of a flapping appendage) can be programmed separately, which is certainly difficult to achieve when working with a live animal."<ref>{{cite journal | last1 = Lauder | first1 = G. V. | year = 2011 | title = Swimming hydrodynamics: ten questions and the technical approaches needed to resolve them | url = http://www.people.fas.harvard.edu/~glauder/reprints_unzipped/Lauder.Exp.Fluids.2011.pdf | journal = Experiments in Fluids | volume = 51 | issue = 1 | pages = 23–35 | doi = 10.1007/s00348-009-0765-8 | bibcode = 2011ExFl...51...23L | s2cid = 890431 | access-date = 2012-11-20 | archive-date = 2019-12-06 | archive-url = https://web.archive.org/web/20191206114306/http://www.people.fas.harvard.edu/~glauder/reprints_unzipped/Lauder.Exp.Fluids.2011.pdf | url-status = live }}</ref>

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