The weaving of the animals -whether a lizard , a cockroach or a fish is a good strategy. So found a study led by engineers at the Johns Hopkins University , Baltimore (USA) .
The researchers found that moving that way , to walk, fly or swim , actually helps increase stability and maneuverability of the animal and is not a waste , as was thought .
Not only that, but combining the two is something that "often engineering texts describe as impossible ," said the American university in a statement.
"One thing they teach you in engineering classes is that you can not have , at the same time , stability and maneuverability ," said research supervisor , Noah Cowan , who is a professor of Mechanical Engineering at Johns Hopkins.
" The Wright brothers soon realized this when they built their first aircraft , he added. For maneuverability needed for the flight had their planes were a bit unstable. "
Cowan said that this discovery " could help engineers to simplify and improve " the design and control systems for small robots that fly, swim or move with mechanical legs .
The research was published this week in the journal Proceedings of the National Academy of Sciences (PNAS ), the official weekly publication of the National Academy of Sciences of the United States.
movements of a fish
For the study , researchers filmed in slow motion movements of a fish knife glass.
The sternopygidae measures about four inches long . Lives in rivers and lakes of South America, and sometimes concealed in tubes or other shelters to avoid predators .
Experts wanted to determine how the glass knife fish fins used to stay in those tubes where there is a steady flow of water in the tank.
"What is immediately obvious in the videos in slow motion, the fish is constantly moving their fins to produce opposing forces ," said Eric Fortune , co-author and professor of biological sciences at the Institute of Technology in New Jersey.
"The mechanism rather contradicts common sense , as two propellers that push against each other ," he said , quoted by the website of Johns Hopkins.
According to the study , the mutually opposing forces that help the fish knife glass is stable and has maneuverability can be found in hummingbirds and bees.
The team developed a mathematical model that determined that this mechanism allows the animal while improving handling and stability, and then tested in a robot that mimicked the movement of the fish.
This robot was developed in the laboratory of Malcolm MacIver , coauthor of the study and associate professor of mechanical and biomedical engineering at Northwestern University ( Illinois, United States) Teacher . " We are far from copy to copy agility animal with the most advanced robots ," said MacIver .
" One interesting finding of this work , he added, is that it is possible that we are not doing more agile machines because we assume that it is a waste or it is useless to have forces in different directions to which we are trying to reach. Turns which is key to greater agility and stability. "
If an animal or a vehicle is stable , the researchers explain , resists changes in direction. But if it is unstable , has the ability to change direction quickly .
Engineers tended to assume that a system could not have both properties.
However, some animals may be the exception.
"Animals often are much more intelligent in its mechanical operation ," said Cowan .
" With the use of a little extra energy to control the opposing forces created during those brief changes of direction and that increases both stability and maneuverability when they swim , run or fly ," he added .