Amphibian robots

September 19, 2000

A walking, swimming salamander comes alive, inside a computer

A ROBOT that can both walk and swim has been simulated in California. Understanding the complex behaviour involved in switching from trotting to swimming could lead to a new generation of amphibious robots, say researchers.

Auke Ijspeert and Michael Arbib of the Brain Simulation Laboratory at the University of Southern California in Los Angeles wanted to investigate how behaviour emerges from simple signals in a creature's central nervous system. So they built a computer simulation of a salamander's central nervous system, and superimposed it on a computer animation.

The resulting "salamander" exists in a simulated world of flat ground and water. Gravity pulls it down, frictional forces act on its feet as it walks, and swirling inertial forces affect it when it is swimming. "Being able to explore by crawling in and out of the sea is not a trivial problem," says John Hallam of the artificial intelligence department at the University of Edinburgh. "There is a tremendous niche market for amphibious robots which could be used for navigation and exploration."

Moving from water to land, or vice versa, is a tough problem for a robot, because it has to completely change its gait and adapt to the new environment, without stopping. Robotic designers have traditionally tried to solve this by breaking down the problem into parts and solving them individually. But this approach is too inflexible, says Ijspeert.

Animals deal with this problem by using sensory inputs as switches that turn different neural control mechanisms on or off. These in turn are transformed into complex and coordinated movements in the body. Through studying salamanders, Ijspeert and Arbib were able to test various ideas about how different neural mechanisms worked-and see how vertebrates control their bodies.

By copying natural oscillators in the brain that produce rhythmic signals for various types of movement, the researchers were able to produce quite complex behaviours. "The circuits are capable of generating trotting and swimming gaits," says Ijspeert. As the robot "sees" water approaching, or feels it, a series of neurological switches make it change from the trotting oscillator to the undulating swimming oscillator.

According to Ijspeert, the salamander was an ideal choice because it has many similarities with humans, but on a simpler scale. "It's a living fossil of one of the first vertebrates that made the transition onto land," he says. He believes his research will help us learn more about our own control mechanisms.
Author: Duncan Graham-Rowe

More at:

New Scientist issue: 23rd September 2000


New Scientist

Related Brain Articles from Brightsurf:

Glioblastoma nanomedicine crosses into brain in mice, eradicates recurring brain cancer
A new synthetic protein nanoparticle capable of slipping past the nearly impermeable blood-brain barrier in mice could deliver cancer-killing drugs directly to malignant brain tumors, new research from the University of Michigan shows.

Children with asymptomatic brain bleeds as newborns show normal brain development at age 2
A study by UNC researchers finds that neurodevelopmental scores and gray matter volumes at age two years did not differ between children who had MRI-confirmed asymptomatic subdural hemorrhages when they were neonates, compared to children with no history of subdural hemorrhage.

New model of human brain 'conversations' could inform research on brain disease, cognition
A team of Indiana University neuroscientists has built a new model of human brain networks that sheds light on how the brain functions.

Human brain size gene triggers bigger brain in monkeys
Dresden and Japanese researchers show that a human-specific gene causes a larger neocortex in the common marmoset, a non-human primate.

Unique insight into development of the human brain: Model of the early embryonic brain
Stem cell researchers from the University of Copenhagen have designed a model of an early embryonic brain.

An optical brain-to-brain interface supports information exchange for locomotion control
Chinese researchers established an optical BtBI that supports rapid information transmission for precise locomotion control, thus providing a proof-of-principle demonstration of fast BtBI for real-time behavioral control.

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.

Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.

Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.

Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.

Read More: Brain News and Brain Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to