Ground robots are becoming commonplace aids on battlefields and in disaster relief operations around the world. But their effectiveness is being hampered by the proliferation of wireless communication devices. Radio signals jam the robots, which are limited in range by low-power antennas and slow processors.
Troops and first responders in the future would like to send teams of autonomous vehicles out on long distance missions that will require improved communications. To help them, scientists are working on technologies that will allow multiple robots to collaborate and form virtual antenna arrays to overcome dead zones and dropped connections and to amplify the systems’ range while consuming less power.
The concept involves combining two key communications capabilities: beamforming and robotic controls.
San Diego-based Adaptive Communications Research Inc. has developed beamforming software that eliminates or reduces interference and extends signal transmission ranges on devices with limited hardware processors. It is based on an algorithm called non-Eigen decomposition. The beamforming software is well suited for robotic systems, said the company’s president, Garret Okamoto.
Funded by a National Science Foundation grant, ACRi is placing its beamforming technology aboard small four-wheeled vehicles with control systems developed by Santa Clara University’s robotic systems laboratory. The robots maneuver collaboratively as a group into formations of various geometrical shapes including circles, squares and triangles, said the lab’s director Christopher Kitts.
“We have a very specific control technique that we’ve developed that lets you very easily, flexibly reconfigure formations of robots,” he said. This “cluster space” approach allows operators to input the intended formation or shape of the group. The control software then calculates each robot’s corresponding movements and sends the vehicle into formation. Eventually, the intent is to take the operator out of the equation and enable the robots to adjust their positions autonomously.
Equipped with ACRi’s beamforming technology, the robots essentially form smart antenna arrays. When they move into different formations, they alter the array’s aperture, which changes the frequency being transmitted or received.
“Basically, there are numerous antennas spread over an area and they are collaboratively communicating. This could be useful in a public safety or disaster situation when it’s tough for a single robot to communicate,” said Okamoto.
In a collapsed building, for example, a group of robots could enter the rubble to conduct a search-and-rescue mission and relay their signals farther than a single system could. The concept would also work on a battlefield where jamming or interference is problematic.
Last month, the scientists were preparing to demonstrate the integrated systems at a NASA-Ames Research Center test facility at Moffett Field, Calif.
“Putting it together isn’t as critical as it is getting our individual pieces to work,” said Okamoto, who added that ACRi has been testing its hardware in simulations that showed the concept would work on two robots to eight robots.
In the demonstration, the researchers planned to test what formations are best for beamforming.
“The idea is to go through a couple basic changes in formation and still have the robots functioning as a single aggregate antenna and have that aggregate antenna working better than a single antenna,” said Kitts.
The four robots will carry a small antenna connected to a box containing a software-defined radio. They will communicate over the Wi-Fi band.
“All the processing and combining happens on one robot. You could use legacy equipment really and just have the upgraded system on one,” said Okamoto.
In addition to seeking opportunities with military robot manufacturers, the company is considering a number of civilian applications for its technology. The software could reside aboard robots designed for disaster recovery and law enforcement missions. Fire fighters are beginning to send robots into burning buildings to determine what areas are safe. Extending the robots’ capability to communicate in those situations might help to save lives, Okamoto said.
“We’re giving him an extra degree of freedom now,” said Kitts, referring to the robots’ mobility and how that impacts Okamoto’s typically stationary antennas. “He can electronically change things, but now we can move the antenna and rearrange the antenna in addition to his electronic changes. Overall, the hope is that that’s going to open up all sorts of new opportunities,” he said.
The Santa Clara researchers have transferred the robotic control and formation technology from ground vehicles to autonomous kayaks. They will test those maritime robots during an upcoming mission with the U.S. Geological Survey.
Okamoto said the beamforming technology could function aboard those platforms as well. “The communications won’t really care if we’re on either platform,” he said. A long-term goal is to adapt the system to satellites.