3D-printed shape-shifting robots developed by the US Army
Image credit: us army
A new breed of 3D-printed robots that can squeeze into tight spaces like a crack in the wall of a cave, jump over tripwire or crawl under a vehicle have been developed at the US Army’s Institute for Soldier Nanotechnologies.
The new approach utilises a 3D printing platform fitted with an electromagnet nozzle and a new type of 3D-printable ink infused with magnetic particles.
Researchers at the US Army's Institute for Soldier Nanotechnologies, based at MIT, claim their work could lead to new biomedical applications, magnetic ink optimised to strengthen soft robotic functionality, and on-demand flexible material systems for use by soldiers.
The technology could enable the US Army to fabricate magnetic 3D-printed structures that can crawl, roll, jump or grab in support of its relevant needs.
The research allows the magnetic orientation of newly 3D-printed devices to be manipulated so that they are able to rapidly change into new intricate formations or move about as various sections respond to an external magnetic field.
Functions demonstrated from these complex shape changes include reconfigurable soft electronics, mechanical metamaterial that can jump, and a soft robot that can crawl, roll, catch fast moving objects or deliver pharmaceuticals.
“This research provided new insight on ways to cause fast changes in three-dimensional shapes of parts such as robot’s limbs,” said Dr Alex Hsieh who worked on the project.
The scientists demonstrated the effect using auxetic metamaterials - synthetic composite materials that have an unusual internal structure and the unusual property that when exposed to external magnetic actuation, they shrank in both longitudinal and transverse directions.
This is different from typical auxetic materials that do require direct mechanical contact, and when compressed they undergo contraction in the directions perpendicular to the applied force (the 'negative Poisson’s ratio').
On the contrary, common materials expand in the directions orthogonal to compressive load. In one example from this research, through remote magnetic control, a metamaterial structure was made to jump forward 120 mm within 0.7 seconds, which is very fast for the current state of the art.
This jump was due to a rapid release of elastic and magnetic potential energy stored in that structure. Such complex shape-morphing structures could have great potential for military applications, because they could help create soft robots with pliable limbs similar to natural organisms.
“Compared to the current generation of rigid robots, soft robots could move much more dexterously on a complex battlefield terrain,” said Hsieh.
“We have developed a printing platform and a predictive model for others to use. People can design their own structure and domain patterns, validate them with the model, and print them to actuate various functions. By programming complex information of structure, domain, and magnetic field, one can even print intelligent machine such as robots,” said MIT Professor Xuanhe Zhao.