London, December 7 : Japanese researchers have developed a humanoid robot that has the ability to rebalance itself after accidental or intentional shoves or kicks land anywhere on its body.
This could become possible due to software written by programmers at the Advanced Telecommunications Research Institute International.
This is also the first incidence when a full-size humanoid, actually made by US firm Sarcos, has been given such qualities.
According to the researchers, this robot can easily rebalance when its arms are pulled into different positions. They believe that the ability to rebalance should allow humans to interact more naturally with robots, and let them act as a physical guide.
The researchers have revealed that their robot's balancing ability depends on its flexible joints, which have been fixed with force sensors. They say that forces sensors within each joint work out the position and velocity of the robot's centre mass as it moves around.
Control software rapidly figures out what forces the robot's feet need to exert on the ground to bring it back into balance and tells the joints how to act, they add.
The researchers say that besides keeping the robot steady as it moves itself around, the technique also lets it readjust to sudden, external forces.
Just in case the robot's joints fail to quickly swing its centre of mass back into place, the humanoid ends up staggering in the same manner as a boxer does after a heavy punch. This constitutes several rounds of rebalancing, with each cycle shifting the centre of mass closer to its original balance point.
ATR researcher Sang-Ho Hyon says that some other humanoid robots rebalance themselves by measuring changes to the position of each joint. This requires very accurate knowledge of the magnitude of an applied shove, says the researcher, which is difficult to achieve without covering the whole robot with force sensors.
"In our method, when we push the hip, the hip follows the external forces and other joints compensate for the balance," New Scientist quoted Hyon as saying.
Jerry Pratt, a roboticist at the Institute for Human and Machine Cognition (IHMC) in Pensacola, Florida, said: "You just don't see the real good humanoids out there get pushed."
"This team are currently ahead of the pack in terms of having it work on a full robot. Making the robot more compliant instead of stiff is plays a big part in that," he says, and the ability to measure and control the torque force at every joint is also crucial.
A report about the software has been published in IEEE Transactions on Robotics. (ANI)
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