On the plains of Namibia, millions of tiny termites are building a mound of soil, an 8-foot-tall “lung” for their underground nest. During a year of construction, many termites will live and die, wind and rain will batter the structure, yet the colony’s life-sustaining project will continue.Inspired by the termites’ resilience and collective intelligence, a team of computer scientists and engineers at the Harvard School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering at Harvard University has created an autonomous robotic construction crew. The system needs no supervisor, no eye in the sky, and no communication. It uses simple robots — any number of robots — that cooperate by modifying their environment.Harvard’s TERMES system demonstrates that collective systems of robots can build complex, 3-D structures without requiring a central command structure or prescribed roles. The results of the four-year project were presented this week at the AAAS 2014 Annual Meeting and published in the Feb. 14 issue of Science.The TERMES robots can build towers, castles, and pyramids out of foam bricks, erecting staircases that let them reach the higher levels and adding bricks wherever they are needed. In the future, researchers say, similar robots could lay sandbags in advance of a flood or even perform simple construction tasks on Mars.“The key inspiration we took from termites is the idea that you can do something really complicated as a group, without a supervisor, and, secondly, that you can do it without everybody discussing explicitly what’s going on, but just by modifying the environment,” said principal investigator Radhika Nagpal, the Fred Kavli Professor of Computer Science at SEAS. She is also a core faculty member at the Wyss Institute, where she co-leads the bio-inspired robotics platform.Most human construction projects are performed by trained workers who operate in a hierarchical organization, said lead author Justin Werfel, a staff scientist in bio-inspired robotics at the Wyss Institute and a former SEAS postdoctoral fellow.“Normally at the beginning, you have a blueprint and a detailed plan of how to execute it, and the foreman goes out and directs his crew, supervising them as they do it,” he said. “In insect colonies, it’s not as if the queen is giving them all individual instructions. Each termite doesn’t know what the others are doing or what the current overall state of the mound is.”Instead, termites rely on a concept known as stigmergy, a kind of implicit communication. They observe each other’s changes to the environment and act accordingly. That is what Nagpal’s team has designed the robots to do. Supplementary videos published with the Science paper show the robots cooperating to build several kinds of structures, and even recovering from unexpected changes to the structures during construction.Each robot executes its building process in parallel with others, but without knowing what else is working at the same time. If one robot breaks, or has to leave, it does not affect the others. This also means that the same instructions can be executed by five robots or 500. The TERMES system is an important proof of concept for scalable, distributed artificial intelligence, researchers say.Nagpal’s Self-Organizing Systems Research Group specializes in distributed algorithms that allow very large groups of robots to act as a colony. Close connections among Harvard’s computer scientists, electrical engineers, and biologists are key to her team’s success. The researchers created a swarm of friendly Kilobots a few years ago and are contributing artificial-intelligence expertise to the ongoing RoboBees project, in collaboration with Harvard faculty members Robert J. Wood and Gu-Yeon Wei.“When many agents get together — whether they’re termites, bees, or robots — often some interesting, higher-level behavior emerges that you wouldn’t predict from looking at the components by themselves,” said Werfel. “Broadly speaking, we’re interested in connecting what happens at the low level, with individual agent rules, to these emergent outcomes.”Co-author Kirstin Petersen, a graduate student at SEAS with a fellowship from the Wyss Institute, spearheaded the design and construction of the TERMES robots and bricks. These robots can perform all the necessary construction tasks — carrying blocks, climbing the structure, attaching the blocks, and so on — with only four simple types of sensors and three actuators.“We co-designed robots and bricks in an effort to make the system as minimalist and reliable as possible,” Petersen said. “Not only does this help to make the system more robust, it also greatly simplifies the amount of computing required of the onboard processor. The idea is not just to reduce the number of small-scale errors, but more so to detect and correct them before they propagate into errors that can be fatal to the entire system.”In contrast to the TERMES system, it is currently more common for robotic systems to depend on a central controller. These systems typically rely on an “eye in the sky” that can see the whole process, or on all of the robots being able to communicate frequently with each other. These approaches can improve group efficiency and help the system recover from problems quickly. But as the number of robots and the size of their territory increase, these systems become harder to operate. In dangerous or remote environments, a central controller presents a single failure point that could bring down the whole system.“It may be that in the end you want something in between the centralized and the decentralized system. But we’ve proven the extreme end of the scale: that it could be just like the termites,” said Nagpal. “And from the termites’ point of view, it’s working out great.”The research was supported by the Wyss Institute.
Point guard Jordan Taylor and the rest of the Badgers walked away from a game at the Kohl Center empty-handed for the first time in 23 games. Taylor led the way with 13 points.[/media-credit]The Wisconsin men’s basketball team snapped a 23-home-game winning streak Saturday in a frustrating 54-61 loss to its biggest in-state rival, the No. 16 Marquette Golden Eagles.Despite taking Marquette’s (7-0) lead down to one point at the 10:45 mark in the second half, No. 7/9 Wisconsin (6-2) was never able to make up for the fact that it couldn’t shut down Marquette’s prolific offense. Down 41-40 in front of a rowdy Kohl Center crowd, Golden Eagle guards Todd Mayo and Darius Johnson-Odom sealed the Badgers’ fate by sinking their shots when it mattered most.Marquette’s defense held Wisconsin scoreless for more than three minutes after the Badgers closed in on the lead, ending any hope of a comeback in a game often dominated by the Golden Eagles on the offensive end.“I thought that the 10 consecutive stops that we got after they brought it to within one was absolutely critical,” Marquette head coach Buzz Williams said. “The guys that we had on the floor amidst that run was a collection of guys that have never even dreamed of playing in a situation like they were in.”With starting point guard Junior Cadougan suspended for a violation of team rules, the Golden Eagles relied on Mayo off the bench to fill the void of Cadougan’s 7.7 points per game.Down by 10 at halftime after shooting a disappointing 26 percent from the field and 14 percent from beyond the arc, the Badgers found themselves in a double-digit hole for a good portion of the second half. Allowing the Golden Eagles to build a lead as high as 12 in the first five minutes of the second period, Wisconsin struggled with its shooting throughout the game as only one player, senior point guard Jordan Taylor, finished with double figures.“I’m sure they want to take the ball out of my hands or whatever, but we got guys who are plenty capable of making plays,” Taylor said. “As a team, we’ve got guys who are capable of making plays – we’re not worried about what people are doing to us, it’s more worried about what we’re doing.”Taylor, who turned the ball over an uncharacteristic five times, failed to ever really find a rhythm as Marquette sustained a lead for most of the game.Wisconsin controlled the lead early in the first half and forced a back-and-forth contest for much of the first 20 minutes, but once the Golden Eagles found their stroke, they never looked back.Led on offense by Johnson-Odom (17 points, five rebounds) and Mayo (14 points, five rebounds), Bo Ryan’s squad solidly contained Marquette’s athletic offense but was unable to get its own shots to fall. The Badgers finished the game shooting 32 percent from the field and 26 percent from beyond the arc, a major slide from a team that was shooting the lights out through its first six games.“[Darius Johnson-Odom] made some tough shots down the stretch, [Todd Mayo], he did too, but like I said, I think it was just we let them get comfortable doing things that they’re used to doing,” Taylor said. “We’re good at taking guys out of their comfort zone, and we just didn’t do that.”As the clock wound down, Wisconsin continued to fight for a victory in front of its home crowd, taking the Golden Eagles’ lead to three with just over two minutes to play. However, Johnson-Odom, along with the support of forwards Jamil Wilson and Davante Gardner off the bench, made sure that the late run was not enough to make up for the Badgers’ offensive struggles.In a physical contest, Marquette won the rebounding battle with 44, including 17 on the offensive end that gave them plenty of second-chance scoring opportunities.“I think they did a good job playing physical, I think they were even more physical than a North Carolina team,” redshirt junior forward Ryan Evans said. “They were playing more Big Ten ball out there, and I think that showed on the rebounds.”Aside from Taylor, UW’s top scorer was guard Ben Brust, who provided a spark off the bench with nine points. Relying too heavily on their perimeter shooting and posting just 16 points in the paint, the Badgers showed that their lack of a dominant inside game can hurt them when shots aren’t falling from outside.Although Wisconsin dropped its second straight game to a ranked opponent Saturday, head coach Bo Ryan still sees much to like in in his team as it heads into the heart of the regular season.“I like some things that I’ve seen this week, and I think those things are going to benefit us later,” Ryan said. “This was a heck of challenge, the next game will be a challenge. But I just saw some things that I really liked, and we saw some things that we know we have to work on.”