Now, a robot that climbs walls by throwing its weight around

London, March 21 : Scientists at Stanford University, California, US, have developed a four-limbed robot that can shift its weight to stay balanced while scaling vertical walls, just like a human climber.

The robot, called Capuchin uses its foot- and handholds to climb vertical walls, says the research team.

Scientists said that Capuchin and other climbing robots could play a key part in uncovering the cliffs of Mars and reveal new information about the planet's geology.

The robot, according to the researchers, cautiously balances its weight across its arms and legs by using force sensors in the tips of its limbs.

They added Capuchin can climb approximately 40 times faster than an earlier climbing robot built by the team.

Built by Stanford and NASA's Jet Propulsion Laboratory (JPL) in California in 2003, the robot, Lemur, could only finish 11 moves of its arms and legs in one hour, whereas Capuchin can complete four in 30 seconds.

"Capuchin's climbing is more human in terms of speed and agility. When you look at Lemur, it's hard to tell if it's climbing; it moves very slowly," New Scientist magazine quoted Teresa Miller, who worked on the 7kg robot before leaving Stanford last year, as saying.

She added that the boost in the robot's performance isn't because of better mechanical design, but rather a more superior computer program that directs the robot's every move, reports New Scientist magazine.

"It was a bit of a step backwards mechanically, but that enabled us to advance significantly with our algorithms," she said.

She further explained that those algorithms include the refined load-balancing system that allocates its weight uniformly among its arms and legs, thus providing Capuchin with greater stability when shifting between supports during a climb.

The software behind Lemur, on the other hand, simply controlled the position of its arms and legs.

Additionally, Capuchin has fewer joints in its arms and legs than Lemur, which prevents it from tackling anything but a flat, vertical surface, for the time being.

A video camera has been recently added to the robot's right hand by Stanford researcher Ruixiang Zhang.

Zhang said that he is planning to fix cameras on all its limbs to permit Capuchin to scale without knowing the location of foot and hand holds in advance.

However, even with the project continuing, robot climbers developed by the Jet Propulsion Lab for use on Mars are expected to stay comparatively slow and unintelligent, due to constraints on computing power that don't apply on Earth.

"You can only make a flight processor so fast, because it needs to be thick and heavy so it can take hits from high energy particles [cosmic rays] and still survive," said Mike Garrett of NASA's JPL.

ANI