Communications of the ACM
Here Come the Swarmbots
Swarmbots created at EPFL, the Swiss Federal Institute of Technology in Lausanne, can communicate with one another and work as a swarm to complete a mission together.
Credit: EPFL
Researchers at Switzerland's École Polytechnique Fédérale de Lausanne (EPFL, the Swiss Federal Institute of Technology in Lausanne) have developed palm-sized, prototype 'swarmbots' that can communicate with one another and swarm en masse to complete a mission working as one.
Looking like three matchbook covers glued together to form the letter "T," the prototype bots—which are essentially circuit boards—can be produced cheaply, according to the researchers. Plus, they are perfectly suited to swarming disaster sites and similar locations that are tough for humans to navigate.
"With their unique collective intelligence, our tiny robots can demonstrate better adaptability to unknown environments; therefore, for certain missions, they would outperform larger, more powerful robots," says Jaime Paik, founder and director of EPFL's Reconfigurable Robotics Lab and a member of the research team.
EFPL's swarmbots are also unusual in that they use jumping as a means of locomotion, which is facilitated by the fact that they are extremely light in weight, at 10 grams each. "A 10-gram, ant-like robotic platform working autonomously is actually an innovation," says Julien Serres, an associate professor at Aix Marseille University who specializes in biorobotics. "This kind of robotic platform will open new opportunities to develop an insect-like robotic platform."
Gülden Köktürk, an assistant professor in the department of electrical and electronic engineering of Turkey's Dokuz Eylül University, agrees. "I think the most important feature of the robot-ant developed in this study is that it is quite light and has good mobility."
EFPL's swarmbots have also received positive reactions from a number of researchers in robotics. "This is truly a big step forward for swarm robotics," says Josh Bongard, a professor in the college of engineering and mathematical sciences of the University of Vermont who specializes in evolutionary robotics. "One of the largest challenges in this field has been to create large numbers of relatively simple, yet autonomous, bots," Bongard says. "This requires making each member of the swarm quickly and cost effectively.
"Paik and her colleagues' approach, combining several layers of functional materials, yet ending up with a 3D structure, is another step toward scalable robot swarms."
Heiko Hamann, a professor at Germany's University of Luebeck specializing in swarm robotics, agrees. "This is impressive research. Jumping is a great choice for locomotion, as tiny robots could be produced that could, for example, stay stopped to recharge by solar energy and then do the next jump, etc. Jumping also allows them to go 'off-road,' as showcased in the paper."
EFPL equipped the bots with infrared and proximity sensors to assess their environment and communicate with one another, according to Zhenishbek Zhakypov, a doctoral assistant at EPFL specializing in robotics and lead author of the research.
Like many tiny bots, EFPL's swarmbots are able to get around by crawling from place to place. But EFPL's researchers decided adding jumping as a locomotion alternative would enable to bots to navigate much tougher terrain and get in and out of nooks and crannies much more easily.
Their solution: find a way to model in their software the jumping escape strategy that Odontomachus ants use when faced with danger. That strategy enables Odontomachus ants to quickly lunge away from a tough predicament by snapping their jaws together and leaping from leaf-to-leaf, according to Zhenishbek.
Once the researchers programmed their software to replicate that movement, all they had to do was add springs to their miniature swarmbots to enable the snapping jaw-like motion.
Ultimately, modeling Odontomachus ants' escape strategy greatly added to locomotive versatility of EFPL's swarmbots, which is manifested in five distinct gaits: Vertical jumping, horizontal jumping, somersaulting to clear obstacles, walking on textured terrain and crawling on flat surfaces.
The researchers also decided to mimic ants in their software by programming the swarmbots to instantly take on varying roles when assigned a mission. "Basically, they can be configured as a leader, a worker, a follower, or as a coordinator robot," says EFPL's Zhenishbek, naming some of the roles available.
Another beauty of the system: any bot can switch roles instantly when needed. That comes in handy if one or more swarmbots get lost in tough terrain, or if a bot meets an unexpected end. Says Pai, "Since they can be manufactured and deployed in large numbers, having some 'casualties' would not affect the success of the mission."
Kasper Stoy, a professor in Denmark's IT University of Copenhagen who specializes in robotics and artificial intelligence, agrees that the cheap-but-sophisticated formula behind the EFPL design is a winner. "The key change (advanced by the research) is the robots are relatively complex while still potentially cheap to produce," Stoy says.
Stoy said the Kilobots developed by Radhika Nagpal and Michael Rubenstein at Harvard University could be seen as competitors to EFPL's swarmbots, but the Kilobots' communications capability is extremely limited, and they can only locomote on flat surfaces.
Another EPFL project yielded the E-puck mobile robots often used in swarm robotics research, "but again, the E-pucks are quite complex and costly," Stoy says.
Tianqi Sun, CEO, of Vincross, a Beijing, China-based technology company that designs, develops, and sells consumer robotics, is encouraged by the researchers' emphasis on collaboration. "This is a very important direction of work, because productivity comes from collaboration," Sun says. "The current industrial robots generally work independently or have very limited and rigid cooperation, which is a bottleneck for the productivity of robots."
The researchers still have work to do before commercial offers come knocking, according to Stoy. "Applications are still some way off, because these robots are not designed to be dirt- and water-resistant," he says. "Hence, direct applications of swarms of robots is maybe still in the realm of science fiction, but every little step makes it more likely we could have a swarm of micro-robots inspecting hard-to-reach areas, whether it being underground in our pipes and sewers or even in space."
Serres agrees. He is looking for a swarmbot that is more ant-like; something that has six legs rather than three. In addition, "This ant-like robot (from EFPL) is devoid of any vision process to control its orientation in space, yet low-resolution visual process are massively used by ants," Serres says. "Moreover, navigating and communicating on the basis of emissive electromagnetic waves will be particularly power-hungry, and will drastically reduce the robot's range."
Ping Ma, an assistant professor of statistics at the University of, believes communications between EFPL's swarmbots could be enhanced if the researchers relied on decentralized computing, because it "focuses on how to fuse the information collected from each node/robot effectively, under the setting that the data collected within each node may contain different types of data heterogeneity."
"Our lab has been working on decentralized computing for years," Ma adds. "The algorithms we developed may benefit their research."
Joe Dysart is an Internet speaker and business consultant based in Manhattan, NY, USA.
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