They are still learning to move

Sep 27, 2007 10:36 GMT  ·  By

There's quite a long way to go till we will have robotic wives and husbands around the house; so, for the moment, it seems that our dogs in the near future might just be ? made of metal (or plastic). If not around the house, at least in the conflict areas. The four-legged dog robots are now the size of a Chihuahua, but could facilitate many military tasks.

The robot called LittleDog could ultimately lead to more complex robotic assistants for troops, like automated "pack-mules" carrying heavy loads over a tough terrain. Scientists are focusing on developing it for even faster and more animal-like movements over uneven terrain.

LittleDog is the creation of a robotic company named Boston Dynamics for the US Defense Advanced Research Projects Agency (DARPA). Recently, DARPA has chosen six university teams, MIT and Stanford included, in a contest for developing the mechanism for controlling the robot pooch.

The mechanic dog has three motored joints on each leg, whose movements are coordinated precisely by an on-board computer. An inner gyroscope is aimed to make the robot detect its orientation, while an outer motion-capture system keeps watch on the precise position of each limb and joint while walking.

The teams have received a LittleDog and a copy of the artificial terrain the device has to cross. Monthly, each team transmits to DARPA its progresses in developing control algorithms, which are tested by the agency to see which results in a faster movement.

By 2008, new algorithms will be applied for more unpredictable terrain. Future algorithms should quickly assess footholds and the best path across the terrain, and at the end of 2008, a winner will be chosen. "Most LittleDog teams are starting to move from a static approach that involves keeping three of the robot's legs rooted to the ground to a more dynamic one that sees only two legs planted at any time.", said Jerry Pratt, a member of the LittleDog team at the Institute for Human and Machine Cognition (IHMC) in Florida. "It's a lot trickier because you have to take dynamics into consideration," Pratt told New Scientist. "Walking becomes more like controlled falling."

Future LittleDog should investigate the terrain ahead for themselves. "It would have to identify the best places to step," said Pratt.

Boston Dynamics has also developed a much larger four-legged robot dubbed BigDog. Internal sensors and motors permit this robot to quickly regain its balance following slipping or pushes, but this robot cannot cross the irregular terrain like LittleDog does. "Legged locomotion on extreme terrain is a very complex task for robots. Adaptive learning offers the best hope of tackling such a complex problem. Think of a human baby learning how to crawl. Initially, the baby does not know how to coordinate the complex motion of its limbs for crawling, but learns by trial and error, and eventually learns how to walk and even run.", said Dennis Hong, an expert on walking robots at Virginia Tech, US, not involved in any of these projects.

"Robots capable of covering such hazardous terrain could find plenty of uses: from search and rescue operations to exploration of unknown areas, and maybe an alternative form of transport for humans in terrains inaccessible by vehicles on wheels like mountains or forests.", said Max Lungarella, a robotics researcher at the University of Zurich (Switzerland).