PORTLAND, Ore. Microminiaturization has made possible swarms of autonomous robots using nothing more than off-the-shelf parts. But concentrating their wireless chatter and getting them to cooperate to solve problems may be five years away, the National Science Foundation cautions. It's putting $2.6 million into a five-year effort to turn multiple wireless robots into an emergency search-and-rescue team.
"We want to help emergency response personnel by sending cooperative robots into an unknown site," said California Institute of Technology researcher Joel Burdick. "My team will be developing software that enables each of them to perform slightly different tasks that together accomplish the goal."
Burdick's group is one of three working on the project, which also includes the University of Minnesota and University of Pennsylvania.
The principal investigator for the project, Nikos Papanikolopoulos, directs Minnesota's Distributed Robotics Lab, which built two of the robots.
Penn researchers, led by professor Kostas Daniilidis, bring expertise in robotic vision and perception, as well as experience in the control theory needed for omnidirectional cameras and team coordination.
The program envisions coordinating multiple robots to carry out emergency workers' complex, high-level commands, such as "search this site for survivors" or "draw a map showing which walls are collapsed."
A series of programming steps must be carried out to enable a single operator to manage swarms of robots. They include software for collaborative sensing, software for distributed exploration and mapping, software for reliable team coordination (both with a human operator and without one) and effective ways to communicate with both the robots and the human operators.
Papanikolopoulos and the Minnesota team have worked on the robot hardware in previous NSF contracts. The result is the 3.9- x 1.4-inch Scout and its 15-inch-long big brother, Mega-Scout, which concentrates communications from Scouts before sending them back to the human operator.
Both units are shaped like tubes about a third as wide as they are long. The Scout is about the size of the cardboard tube inside a toilet tissue roll, the MegaScout about the size of Sunday's paper rolled up. The cameras and other sensors are recessed into the surfaces of the tube. Sensors include video cameras, infrared range finders, two different types of light detectors and a pyroelectric sensor. Each unit is also equipped with a wireless frequency-hopping, signal-encrypting transceiver. A mechanical "foot" can roll the tube for limited locomotion.
Papanikolopoulos' group built the Scout and MegaScout from off-the-shelf electronic subassemblies mounted on rugged internal shock mounts that can withstand a 100-foot "throw" into unknown territory or a six-story drop, for instance, in a collapsed building. People, drones or even the MegaScout can drop or throw a Scout into an area to extend the sensor net's coverage.
For pure surveillance, Scouts can spread out evenly and find dark corners from which to silently observe, but in emergency situations the most important tasks will involve the Scouts cooperating-with themselves and with the MegaScout-to accomplish the human operators' high-level goals. Guided by emergency workers, such robot swarms can collect air samples, test for toxic fumes and draw maps marked with items of interest as well as fulfill their principal mission: locating survivors.
Today, emergency workers who already operate remote-control robots, Papanikolopoulos said, can at most handle only three at one time, making the autonomous management of robot swarms a task for advanced software. Besides carrying larger sensors, the MegaScout also has a manipulator arm that can unfold for opening doors, throwing Scouts or lifting them out of trouble. The MegaScout will monitor communications among the autonomous Scouts, issue commands, arbitrate disputes (such as when two robots "decide" to search the same dark corner), relay data back to the human operator and maintain communications with other MegaScout robots. By hierarchically designing their software, the teams hope to enable swarms of hundreds of Scouts to be managed by human operators who need to control only three or fewer MegaScouts.
"For Darpa [Defense Advanced Research Projects Agency] we have designed many robots for military surveillance-some will be deployed in Iraq very soon," said Papanikolopoulos.
For instance, the TerminatorBOT widens out the diameter of a 100-mm-long Scout from 35 mm to 75 mm, making it resemble a soda can. In the extra space, the TerminatorBOT folds two three-degree-of-freedom arms that are completely retractable and yet have a reach of 170 mm.
In action, the TerminatorBOT can assist the limited-mobility Scouts (which basically only roll forward or backward) by lifting them over obstacles. For military operations, the TerminatorBOT can perform many of the actions that human hands can perform, like using rope, pushing a button or pulling a trigger. It also has a variety of gaits, including ones for swimming and squeezing through narrow passages. In the most powerful, the bumpy-wheel gait, the robot's arms roll to propel its body when it climbs stairs or goes through rough terrain.