Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists Study Some Fishy Behavior to Solve an Animal Locomotion Mystery

06.11.2013
A quirk of nature has long baffled biologists: Why do animals push in directions that don’t point toward their goal, like the side-to-side sashaying of a running lizard or cockroach? An engineer building a robot would likely avoid these movements because they seem wasteful. So why do animals behave this way?

A multi-institutional research team, led by Johns Hopkins engineers, says it has solved this puzzle. In an article published in the Nov. 4-8 online edition of Proceedings of the National Academy of Sciences, the team reported that these extra forces are not wasteful after all: They allow animals to increase both stability and maneuverability, a feat that is often described as impossible in engineering textbooks.

“One of the things they teach you in engineering is that you can’t have both stability and maneuverability at the same time,” said Noah Cowan, a Johns Hopkins associate professor of mechanical engineering who supervised the research. “The Wright Brothers figured this out when they built their early airplanes. They made their planes a little unstable to get the maneuverability they needed.”

When an animal or vehicle is stable, it resists changes in direction. On the other hand, if it is maneuverable, it has the ability to quickly change course. Generally, engineers assume that a system can rely on one property or the other -- but not both. Yet some animals seem to produce an exception to the rule.

“Animals are a lot more clever with their mechanics than we often realize,” Cowan said. “By using just a little extra energy to control the opposing forces they create during those small shifts in direction, animals seem to increase both stability and maneuverability when they swim, run or fly.”

Cowan said this discovery could help engineers simplify and enhance the designs and control systems for small robots that fly, swim or move on mechanical legs.

The solution to the animal movement mystery surfaced when the scientists used slow-motion video to study the fin movements of the tiny glass knifefish. These shy fish, each about 3 inches long, prefer to hide in tubes and other shelters, a behavior that helps them avoid being eaten by predators in the Amazon basin, their natural habitat. In a lab, the team filmed the fish at 100 frames per second to study how they used their fins to hover in these tubes, even when there was a steady flow of water in the fish tank.

“What is immediately obvious in the slow-motion videos is that the fish constantly move their fins to produce opposing forces. One region of their fin pushes water forward, while the other region pushes the water backward,” said Eric Fortune, a professor of biological sciences at the New Jersey Institute of Technology who was a co-author of the PNAS paper. “This arrangement is rather counter-intuitive, like two propellers fighting against each other.”

The research team developed a mathematical model that suggested that this odd arrangement enables the animal to improve both stability and maneuverability. The team then tested the accuracy of its model on a robot that mimicked the fish’s fin movements. This biomimetic robot was developed in the lab of Malcolm MacIver, an associate professor of mechanical and biomedical engineering at Northwestern University and a co-author of the PNAS paper.

“We are far from duplicating the agility of animals with our most advanced robots,” MacIver said. “One exciting implication of this work is that we might be held back in making more agile machines by our assumption that it’s wasteful or useless to have forces in directions other than the one we are trying to move in. It turns out to be key to improved agility and stability.”

The mutually opposing forces that help the knifefish become both stable and maneuverable can also be found in the hovering behavior of hummingbirds and bees, in addition to the glass knifefish examined in this study, said senior author Cowan, who directs the Locomotion in Mechanical and Biological Systems Lab within Johns Hopkins’ Whiting School of Engineering.

“As an engineer, I think about animals as incredible, living robots,” said study’s lead author, Shahin Sefati, a doctoral student advised by Cowan. “It has taken several years of exciting multidisciplinary research during my PhD studies to understand these 'robots' better.”

Other co-authors on the paper were Izaak D. Neveln and James B. Snyder, both Northwestern doctoral students in the Neuroscience and Robotics Laboratory supervised by MacIver; Eatai Roth, a former Johns Hopkins doctoral student now at the University of Washington; and Terence Mitchell; a former Johns Hopkins postdoctoral fellow now at the Campbell University School of Osteopathic Medicine.

This research was supported by National Science Foundation grants 0543985, 0845749 and 0941674, and by Office of Naval Research grant N000140910531.

Phil Sneiderman | Newswise
Further information:
http://www.jhu.edu

Further reports about: Amazon basin Animal PNAS locomotion physical mystery

More articles from Studies and Analyses:

nachricht Drone vs. truck deliveries: Which create less carbon pollution?
31.05.2017 | University of Washington

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Supersensitive through quantum entanglement

28.06.2017 | Physics and Astronomy

X-ray photoelectron spectroscopy under real ambient pressure conditions

28.06.2017 | Physics and Astronomy

Mice provide insight into genetics of autism spectrum disorders

28.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>