Researchers Look at Mechanical Metamaterials


Last month, researchers from the Massachusetts Institute of Technology’s Center for Bits and Atoms and members from a United States Army think-tank published a research paper on the development of a metamaterial that could be used to create robots made from robots.

According to reports, the mass-producible, reconfigurable robots would consist of Lego-style construction bricks with the ability to interlock to form a variety of possible infrastructure, as well as disassemble and return to storage.

The idea, according to Bryan Glaz, associate chief scientist in the laboratory’s Vehicle Technology Directorate, arrives as an example of high-risk exploratory science and technology efforts from the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory. In turn, Glaz said that the idea was then directly motivated by Futuristic visions from concept developers with the Army Future Command’s Futures and Concepts Center at Fort Eustis, Virginia.

Researcher pursued this research based on discussions and concepts supported by The U.S. Army Functional Concept for Movement and Maneuver, which describes how Army maneuver forces could generate overmatch across all domains.

In the paper, the collaborative team wrote, “Here, we present a construction system for mechanical metamaterials based on discrete assembly of a finite set of modular, mass-produced parts. We demonstrate experimentally the desired metamaterial property for each part type and, combined with numerical modeling results, display other unexpected and useful properties. A modular construction scheme enables a range of mechanical metamaterial properties to be achieved, including rigid, compliant, auxetic, and chiral, all of which are assembled with a consistent process across part types, thereby expanding the functionality and accessibility of this approach.”

Through a voxel-based construction system, researchers are specifically looking to employ the use of special AI-generated shapes at the cellular level. The materials—similar to 3D-printed materials—would incorporate interlocking voxel pieces but wouldn’t require a printer to work.

According to the U.S. Army, “The system, based on cost-effective injection molding and discrete lattice connections, enables rapid assembly of macro-scale structures, which may combine characteristics of any of the four base material types: stiff; compliant; auxetic, or materials that when stretched become thicker perpendicular to the applied force; and chiral, or materials that are asymmetric in such a way that the structure and its mirror image cannot be easily viewed when superimposed.”

The ultimate goal being to be able to complete construction projects, but also have the ability to be reconfigured into myriad other designs as well, the team hopes that the technology will one day be able to be produced as a set of self-assembling AI-powered construction materials in the form of a deployable robot swarm.

“Robots rearranging to form a bridge made of robots, similar to ants, is one embodiment of our concept of structural robotics, which blur the line between active and passive elements and feature reconfigurability. It is still a motivating use case for the system, but we are looking at broader implications for ground robotics which are adaptable, reconfigurable, and resilient,” said Dr. Christopher Cameron, an Army researcher. “If a swarm of robots can turn themselves into a bridge, how else can they be rearranged? How do we design and control robots like this?”

Still in early phases of research, a paper on the metamaterial development has since been published in Science Advances, however, next phases plan to involve the exploration of design space created by the system with target applications including modular soft robotics, impact absorbing structures, and rapid construction at the point of demand.

“This part of our high risk, exploratory research portfolio within the Vehicle Technology Directorate,” Glaz said. “In a couple of years we may find there is no major Army advantage to robots-made-robots but right now, we’ve thought of early Army applications such as rapidly forming bridges as well as air dropping or launching a bunch of smaller robots into a contested area and to test how they come together to form a larger mobile platform that can do useful functions in the aggregated phase.”

Construction Robots

Back in March, engineering and robotics design company Boston Dynamics (Waltham, Massachusetts) showcased its latest technology, Spot the robot dog. The robot dog is intended to be used as a vehicle for carrying image capturing or laser scanning equipment where humans might not be able to.

In all of its testing, Spot has been confirmed to be able to carry up to 25 pounds of payload and is able to use up to three different types of scanning or data capturing equipment through both autonomous and remote controlled methods.

A month prior to the announcement, Westminster, Colorado-based space technology company Maxar Technologies was awarded a $142 million contract from the National Aeronautics and Space Administration to develop a robotic technology capable of assembly and manufacturing whilst in orbit.

The company was previously part of NASA’s Tipping Point partnership—announced back in 2015—but now includes partners Tethers Unlimited (Bothell, Washington), West Virginia Robotic Technology Center (Morgantown, West Virginia) and NASA’s Langley Research Center (Hampton, Virginia).

When first developing the technology in 2015, the payload then known as “Dragonfly,” was chosen by NASA’s public-private partnership program to further explore technologies that would specifically perform on-orbit robotic installations and reconfigurations of large solid RF reflectors.

Now in its second phase of the partnership, NASA resources and industry contributions are fueling the project to gear up for a demonstration of the technology, slated to take place on NASA’s Restore-L spacecraft, which is designed to service and refuel satellites in low-Earth orbit.

In changing the development’s name from Dragonfly to SPIDER (Space Infrastructure Dexterous Robot), the payload includes a lightweight 16-foot-long robotic arm which will be used to assemble several elements to form a functional 9-foot-tall communications antenna. GeekWire reports that this procedure was already carried out successfully during a ground demonstration in 2017.

Once robotically assembled, the antenna will be able to conduct Ka-band transmission with a ground station, while the manufacturing element intends to verify the capabilities of in-space construction.

And in December of last year, a collaboration of researchers attending Shanghai-based Tongji University's College of Architecture and Urban Planning’s DigitalFUTURES International summer workshop and local research studio Fab-Union used robots to fabricate a hybrid pedestrian bridge.

To construct the metal fabricated bridge, the team used a novel hybrid additive manufacturing approach that incorporated large-scale 3D printers, filament winding and topology optimization software. According to reports, the total process took only 20 days and four robots to complete.

In a two-part process, the bridge’s skeletal steel base was 3D printed using a robotic fabrication process and then reinforced by winding carbon and glass fibers around the frame to create the handrails and stairs.

In using the topology optimization software, the team was able to remove all unnecessary material prior to construction, which resulted in the use of only 263 kilograms (almost 580 pounds) of steel for the 11.4-meter-long (12.5-foot-long) bridge. The completed structure could hold over 20 people safely and at its thinnest point, was only 20 centimeters thick.


Tagged categories: Colleges and Universities; Construction; Infrastructure; NA; North America; Program/Project Management; Research; Research and development; Robotics; Technology; U.S. Army

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