July 2012
4 posts
Scientists make robotic legs that move like ours do +video
Bipedal robots, in general, are a pretty stilted bunch. Their movements are overarticulated, they wobble, they topple, and when faced with an obstacle even one as slight as a slope change they often can’t overcome it.
But that may soon change. This week, researchers from the Univeristy of Arizona published a paper in the Journal of Neural Engineering that describes the development of a new type of robot legs that mimic the neuromuscular architecture of human walking.
In other words, they created a pair of robot legs that are starting to “think” about walking the same way people do.
In humans, sensory feedback from our environment is constantly being collected by our lower limbs and sent to a network of neurons in the spinal column called a central pattern generator, which uses that information to keep our gait even and steady. That’s what lets us walk without having to consciously think about it.
Using human legs as a model, the scientists put sensors at the bottoms of the robot legs’ feet that tell them whether they are touching the ground. The scientists also gave internal position sensors to each of the motors that pull on the “muscles” in the legs.
The robot legs adapt naturally to changes in their environment. For example, as the legs hit a slight upslope, they will automatically walk slower and push harder, and if they are going downhill, they will walk a little faster.
“The conventional AI paradigm is just do everything with logic, but that doesn’t always work very well,” Theresa Klein, an electrical engineer and neuroscientist who co-authored the paper, told the Los Angeles Times. “We are rebuilding the idea of how do we really move and navigate through the world, and you get these results that are much more lifelike.”
Klein’s research should be able to help in the development of robots that move more the way humans do, but it has other applications too. The legs could be used to do research on the neuroscience of walking, which could especially benefit people with spinal cord injuries that affect their legs.
Worm lifetime 'longer in space
A number of Caenorhabditis elegans worms were carried aboard a mission to the International Space Station (ISS) and brought back for study.
Researchers found reduced activity of five genes in the worms that, when suppressed in the species on Earth, lead to longer lifetimes.
The work appears in Scientific Reports.
The nematode C. elegans is among the world’s most-studied animals.
They have been routinely taken as cargo on space missions to study in a simple organism the biological changes that future human spacefarers may face; the worms even survived the space shuttle Columbia disaster in 2003.
More recently, the prospects for a self-contained and self-sustaining colony of the worms were described in a 2011 paper in the Journal of the Royal Society Interface.
But it was also the first multi-celled organism to have its entire genome sequenced, and researchers are now getting to the bottom of what changes space travel wreaks on the worms’ genomes.
Space age
Nathaniel Szewczyk of the University of Nottingham and researchers from a number of Japanese universities examined worms that were taken for an 11-day trip on the space shuttle to the ISS and then flash-frozen once they returned to Earth.
A “control group” of worms was kept on Earth at the time and frozen at the same time. The lifetime of the worms ranges from two to three weeks, so they were at a fairly advanced age when preserved.
The team found that the muscles of the well-travelled worms exhibited smaller amounts of polyglutamine aggregates, tangles of protein that tended to accumulate in the muscles as animals aged.
But they also found five genes that were more “switched off” than the worms that had stayed on Earth.
The five were involved in signalling in the nervous and metabolic systems, and one that is chemically similar to insulin - the manipulation of which was shown in a 2003 Science paper to enormously increase C. elegans’ lifetime.
“It would appear that these genes are involved in how the worm senses the environment and signals changes in metabolism in order to adapt to the environment,” said Dr Szewczyk.
“Most of us know that muscle tends to shrink in space. These latest results suggest that this is almost certainly an adaptive response rather than a pathological one.
“Counter-intuitively, muscle in space may age better than on Earth. It may also be that spaceflight slows the process of ageing.”
US to Begin New Phase of Hypersonic Flight Program
The Defense Department’s research arm will seek proposals next month for solutions to technology hurdles in super high-speed flight with a goal of testing a full-scale hypersonic X-plane in four years.
The Defense Advanced Research Projects Agency said Friday it will host a so-called Proposers’ Day on Aug. 14 to lay out technical areas for which proposals are being sought.
DARPA has tested highly experimental versions of a rocket-launched unmanned glider designed to fly at speeds 20 times the speed of sound, or Mach 20. The goal is to give the U.S. a defense capability of reaching any spot on Earth in an hour.
But such aircraft have to endure blast-furnace heat and require extraordinary controls.
The last test launch from California ended with the glider’s skin peeling away.
