MIT CSAIL/MARTIN NISSER
The self-assembling and self-reconfiguring robots depicted in films like Transformers are getting closer to reality thanks to a team of researchers from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL). CSAIL scientists have developed ElectroVoxels, modular robotic cubes that move using embedded electromagnets.
“I originally desired to call them Transformers due to the fact they’re essentially robots which can change their shape,” says Martin Nisser, a Ph.D. student in the human-computer interaction group at the MIT CSAIL and lead writer of the paper. Due to copyright reasons, the team decided in opposition to it and settled on combining the term “electromagnet” with “voxel,” a volumetric pixel that’s 3D equivalent of a pixel. “You can consider ElectroVoxels as voxels with electromagnets embedded in them,” he says.
An ElectroVoxel cube certainly has an electromagnet—a ferrite core wrapped with copper wire—embedded into every of its twelve edges. “When you send a current via an electromagnet, the polarization relies upon on the direction in that you send the current,” Nisser says. “It’s like a permanent magnet, besides you could change the polarity relying at the direction of the current.”
ElectroVoxel blocks move-by either pivoting to a block it shares an edge with or traversing the face of one block to any other. When a couple of electromagnets in a cube are polarized oppositely, they attract each other, developing a hinge. You can then use any other pair of electromagnets polarized in the same direction to repel each other and carry-out a pivoting maneuver. Once that pivoting is finish, you could use separate pairs of electromagnets to attract each other and keep the faces of the two cubes together.
The blocks also are programmable. “When you have greater than 2 or 3 ElectroVoxels, it becomes difficult to address every electromagnet individually and predict what’s going to happen,” says Nisser. “So, we created a user interface that helps you to specify which ElectroVoxel ought to pivot in what direction. Then all of the underlying electromagnet assignments are computed for you, and we can put that directly onto the microcontroller.”
Unlike different self-assembling robots whose hardware includes bulky vehicles or pricey actuators, ElectroVoxels promise scalability. They’re light, with every cube weighing 103 grams; cheaper, with every electromagnet costing around US $0.60; and easy to build, with every cube taking approximately 80 minutes to construct.
But ElectroVoxels aren’t without their limitations, and the team took benefit of a specific one as an ideal vehicle for space applications. “One of the drawbacks of ElectroVoxels is that their force is relatively weak as compared to different actuators. Yet we additionally found out that they can be used effectively in space,” Nisser says.
“In a microgravity environment, even very low forces can make a contribution to enormous velocities, so a very small force just like the ones we’ve in ElectroVoxels may want to make a contribution to moving massive objects. We noticed this possibility to discover reconfigurable robots for space applications, wherein you need to attempt to change the inertial properties of spacecraft, or to help construct temporary structures which could be useful resource in numerous activities consisting of structure inspection by astronauts.”
To test their theory and set up reconfiguration in space, the team performed experiments in a microgravity environment. First, they used an air table, a flat table with holes in it and chutes round it to create air pillows that simulate microgravity conditions. The ElectroVoxels successfully carried out pivots and traversals at the air table. Then, the team flew the cubes aboard a parabolic flight to examine pivoting. They encountered a few difficulties, however the ElectroVoxels had been able to pivot in flight.
“On a typical flight, an aircraft flies those parabolas approximately 20 times, and every of the parabolas lasts for around 15 seconds. But the quality of the microgravity inside the ones parabolas tends to vary a bit,” says Nisser. “What ended up happening is that we simplest had approximately 4 seconds of microgravity, so the main challenge was fine-tuning the entirety to ensure we had been as prepared as possible for it to work, because with simply four seconds, there has been no time or capability to update things.”
While the team has tested the ability of ElectroVoxels to be used in space, they wish to do the same in the future for Earth. “We are looking at seeking to optimize ElectroVoxels for torque-to-inertia ratios on the way to pivot against gravity,” Nisser says.
Another fit for Earth application for those re-configurable robots is rapid recyclable prototyping. “3D printers are typically used to create one-off, low-fidelity prototypes that aren’t necessarily functional,” says Nisser. “If you can prototype with a modular system, you can create only structure and have it automatically pivot into a second structure, creating rapid prototyping more sustainable. You would not have to discard the plastic after each print; You’d simply use the same modules to create new structures.
This post had been originally published on IEEE Spectrum.
