Featured Research

from universities, journals, and other organizations

Robotic construction crew needs no foreman

Date:
February 13, 2014
Source:
Harvard School of Engineering and Applied Sciences
Summary:
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 erode the structure, and yet the colony’s life-sustaining project will continue. Inspired by the termites’ resilience and collective intelligence, a team of computer scientists and engineers has created an autonomous robotic construction crew. The system needs no supervisor, no eye in the sky, and no communication: just simple robots—any number of robots—that cooperate by modifying their environment.

The TERMES robots can carry bricks, build staircases, and climb them to add bricks to a structure, following low-level rules to independently complete a construction project.
Credit: Eliza Grinnell, Harvard SEAS

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 erode the structure, and 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: just 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, three-dimensional structures without the need for any central command or prescribed roles. The results of the four-year project were presented this week at the AAAS 2014 Annual Meeting and published in the February 14 issue of Science.

The TERMES robots can build towers, castles, and pyramids out of foam bricks, autonomously building themselves staircases to reach the higher levels and adding bricks wherever they are needed. In the future, similar robots could lay sandbags in advance of a flood, or 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," says principal investigator Radhika Nagpal, Fred Kavli Professor of Computer Science at Harvard SEAS. She is also a core faculty member at the Wyss Institute, where she co-leads the Bioinspired Robotics platform.

Most human construction projects today are performed by trained workers in a hierarchical organization, explains lead author Justin Werfel, a staff scientist in bioinspired 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 says. "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 others' changes to the environment and act accordingly. That is what Nagpal's team has designed the robots to do, with impressive results. 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 who 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 five hundred. The TERMES system is an important proof of concept for scalable, distributed artificial intelligence.

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 between Harvard's computer scientists, electrical engineers, and biologists are key to her team's success. They 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," says Werfel. "Broadly speaking, we're interested in connecting what happens at the low level, with individual agent rules, to these emergent outcomes."

Coauthor Kirstin Petersen, a graduate student at Harvard 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 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 says. "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 talk to each other frequently. These approaches can improve group efficiency and help the system recover from problems quickly, but as the numbers 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," says Nagpal. "And from the termites' point of view, it's working out great."

This research was supported by the Wyss Institute for Biologically Inspired Engineering at Harvard University.

What can a TERMES robot do?

- Move forward, backward, and turn in place

- Climb up or down a step the height of one brick

- Pick up a brick, carry it, and deposit it directly in front of itself

- Detect other bricks and robots in immediate vicinity

- Keep track of its own location with respect to a "seed" brick

What instructions do the TERMES robots follow?

- Obey predetermined traffic rules

- Circle the growing structure to find the first, "seed" brick (for orientation)

- Climb onto the structure

- Obtain a brick

- Attach the brick at any vacant point that satisfies local geometric requirements

- Climb off the structure

- Repeat


Story Source:

The above story is based on materials provided by Harvard School of Engineering and Applied Sciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. Justin Werfel, Kirstin Petersen, Radhika Nagpal. Designing Collective Behavior in a Termite-Inspired Robot Construction Team. Science, February 14, 2014 DOI: 10.1126/science.1245842

Cite This Page:

Harvard School of Engineering and Applied Sciences. "Robotic construction crew needs no foreman." ScienceDaily. ScienceDaily, 13 February 2014. <www.sciencedaily.com/releases/2014/02/140213142134.htm>.
Harvard School of Engineering and Applied Sciences. (2014, February 13). Robotic construction crew needs no foreman. ScienceDaily. Retrieved April 16, 2014 from www.sciencedaily.com/releases/2014/02/140213142134.htm
Harvard School of Engineering and Applied Sciences. "Robotic construction crew needs no foreman." ScienceDaily. www.sciencedaily.com/releases/2014/02/140213142134.htm (accessed April 16, 2014).

Share This



More Computers & Math News

Wednesday, April 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Twitter, Apple Social Data Purchases Likely to Spur More Mergers and Acquisitions

Twitter, Apple Social Data Purchases Likely to Spur More Mergers and Acquisitions

TheStreet (Apr. 16, 2014) The social media data space is likely to see more mergers and acquisitions following Twitter Inc.'s acquisition of tweet analyzer Gnip Inc. on Tuesday and Apples Inc.'s purchase of Topsy Labs Inc. back in December. One firm in particular, the U.K.'s DataSift Inc., could be on the list of potential buyers. Among other social media startups that could be ripe for picking is Banjo, whose mobile app provides aggregated content by topic and location. Banjo could also be a good fit for Twitter. Video provided by TheStreet
Powered by NewsLook.com
Google Patents Contact Lens Cameras; Internet Is Wary

Google Patents Contact Lens Cameras; Internet Is Wary

Newsy (Apr. 15, 2014) Google has filed for a patent to develop contact lenses capable of taking photos. The company describes possible benefits to blind people. Video provided by Newsy
Powered by NewsLook.com
NYPD Ends Muslim Surveillance Program

NYPD Ends Muslim Surveillance Program

AP (Apr. 15, 2014) The New York City Police Department has ended a program that once kept tabs on the city's muslim population. (April 15) Video provided by AP
Powered by NewsLook.com
Images Of Rumored Amazon Smartphone Leaked

Images Of Rumored Amazon Smartphone Leaked

Newsy (Apr. 15, 2014) BGR has leaked images of what could be Amazon's smartphone. The outlet's been right about Amazon leaks before. Sources expect an announcement in June. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins