If you are faced with a choice: send into space a swarm of full-length different robots or a large team of smaller robot modules, you can attract the latter. Modular robots, like those shown in films such as “The Great Hero 6,” have a special type of promise for their ability to self-assemble and reconfigure. But with all the ambitious desire for rapid and reliable deployment in areas that extend to space exploration, search and rescue and reshaping, the modular robots created to date are still a bit awkward. They are usually built from a menagerie of large expensive engines to facilitate movement, which requires a focus on larger scalable architectures – both in number and size.
Scientists from the Massachusetts Institute of Technology’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have called for electromagnetism – electromagnetic fields generated by the movement of electric current – to avoid the usual stuffing of bulky and expensive drives into individual blocks. Instead, they built small, easily manufactured, inexpensive electromagnets at the edge of the cubes that repel and attract, allowing the robots to rotate and move around each other and quickly change shape.
“ElectroVoxels” have a side length of about 60 millimeters, and the magnets consist of ferrite rods (they look like little black tubes) wrapped in copper wire, which cost only 60 cents. Inside each cube are tiny circuit boards and electronics that send current through the right electromagnet in the right direction.
Unlike traditional hinges, which require mechanical fastening between the two elements, ElectroVoxels are completely wireless, making them much easier to maintain and manufacture for a large-scale system.
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ElectroVoxels are robotic cubes that can be reconfigured using electromagnets. Cubes do not need engines or fuel to move, and they can operate under microgravity.
To better imagine what the pile of blocks would look like during the interaction, the researchers used a software scheduler that visualizes reconfigurations and calculates basic electromagnetic tasks. The user can manipulate up to a thousand cubes in just a few clicks or use predefined scripts that encode multiple consecutive rotations. The system really allows the user to control the fate of the blocks within reason – you can change the speed, highlight the magnets and show the necessary moves to avoid collisions. You can instruct the blocks to acquire different shapes (for example, from a chair to a sofa, because who needs both?)
Cheap little blocks are especially conducive to a microgravity environment, where any structure you want to launch into orbit must fit inside the rocket used to launch it. After initial tests on the air table, ElextroVoxels discovered real weightlessness during microgravity flight tests with a general push for better space exploration tools such as reconfiguration without fuel or changing the inertial properties of the spacecraft.
For example, using a fuelless drive, there is no need to run additional fuel for reconfiguration, which solves many problems related to starting weight and volume. Thus, it is hoped that this method of reconfiguration can help many future space efforts: increase and replace space structures during multiple launches, temporary structures to assist in spacecraft inspection and assistance to astronauts, and (future iterations) cubes acting as stand-alone sorting storage containers.
“ElectroVoxels shows how to create a fully reconfigured system, and poses our scientific community with the challenges it needs to solve in order to have a fully functional modular robotic system in orbit,” said Dario Itzo, head of advanced concepts at European Space. Agency. “This study demonstrates how electromagnetic-powered rotating cubes are easy to build, operate and maintain, creating a flexible, modular and reconfigurable system that can inspire the development of intelligent components for future research missions.”
To make the blocks move, they must follow a sequence like small homogeneous pieces of Tetris. In this case, there are three steps in the polarization sequence: launch, travel and fishing, with each phase having a travel cube (to move), an initial one (from where the traveling cube is launched) and a destination (which catches the driving cube cube). Software users can determine which cube needs to be rotated in which direction, and the algorithm will automatically calculate the sequence and address of the electromagnetic jobs required to make this happen (reflect, attract, or exclude).
For future work, moving from space to Earth is a natural next step for ElectroVoxels, which will require more detailed modeling and optimization of these electromagnets to make a reconfiguration here against gravity.
“When building a large complex structure, you don’t want to be limited by the availability and experience of the people involved in its assembly, the size of your vehicle, or the adverse environmental conditions at the assembly site. Although these axioms are true on Earth, they are being seriously strengthened to create things in space, ”said MIT CSAIL graduate student Martin Nisser, lead author of ElectroVoxels. “If you could have structures that are assembled from simple homogeneous modules, you could eliminate many of these problems. Thus, although the potential benefits in space are particularly great, the paradox is that the favorable dynamics provided by microgravity mean that some of these problems are actually also easier to solve – in space even tiny forces can make big things move. By applying this technology to solve real short-term problems in space, we can hopefully incubate the technology for future and ground use. “
Nisser co-authored an article with Leon Cheng and Yashavini Makaram of MIT CSAIL; Rio Suzuki, Associate Professor of Computer Science at the University of Calgary; and MIT professor Stephanie Mueller. They will present work at the International Conference on Robotics and Automation in 2022. The work was partially supported by The MIT Space Exploration Initiative.