This time-lapse photo shows various designs of developed magnetic active material. Source: MIT Soft Active Materials LabWith the ability to squeeze into tight spaces, jump over trip wire or crawl under a vehicle, the U.S. Army’s new crop of soldiers is quite an impressive bunch. But they won’t likely be looking for combat medals for tours of duty: They’re not human. They’re 3D-printed robots.
Through research managed by the U.S. Army Research Laboratory (ARL), a platform to create the soft robotic soldiers was developed by the Army's Institute for Soldier Nanotechnologies (ISN) at MIT. It is designed to enable both the modeling and design of complex, magnetically actuated devices, utilizing an electromagnet nozzle and a new type of 3D-printable ink infused with magnetic particles.
The idea is to control the device's magnetic orientation in order to enable movement and rapid formation changes in response to an external magnetic field. The technology may enable the future Army to fabricate structures that can crawl, roll, jump or grab.
The technique uses auxetic metamaterials — synthetic composite materials that have an unusual internal structure and an unusual property: When exposed to external magnetic actuation, they shrink in both longitudinal and transverse directions.
Printing process and material composition schematics. Source: U.S. Army IllustrationPreviously, other groups have fabricated magnetically-activated materials to accomplish simple movements. But the new platform allows the researchers to program ferromagnetic domains in complex 3D-printed soft materials — enabling a set of previously inaccessible modes of transformation. Actuation speed and power density, moreover, is orders of magnitude greater than existing 3D-printed active materials.
“Compared to the current generation of rigid robots, soft robots could move much more dexterously on a complex battlefield terrain," said Dr. Alex Hsieh of the ARL.
In addition to combat applications, the researchers’ findings could lead to new biomedical applications; magnetic ink optimized to strengthen soft robotic functionality; and new, on-demand flexible material systems for integration into soldier systems.
Soft robotic capabilities and point-of-need manufacturing are among the Army's top research priorities.
