Lots of people make their own robots, and in all sorts of ways, but have you ever heard of anyone baking one in an oven? Researchers at MIT have demonstrated how to create self-assembling bodies that fold together when baked, as well as showing how a similar technique can be used to generate electronic components to control them.
Based primarily on research conducted in the lab of Daniela Rus, Professor of Electrical Engineering and Computer Science at MIT, the group from MIT, the University of Zurich and the University of Tokyo presented two papers describing this robot baking process at the IEEE International Conference on Robotics and Automation.
The first paper describes a system that takes a digital rendering of a 3D shape and produces 2D patterns to be created in plastic. When these cutouts are heated, they reproduce the original 3D shape through self-folding. In the second paper, the team goes on to explain how to construct electronic components from similar, self-folding, laser-cut materials. In this case, the researchers present designs for resistors, inductors, capacitors, and sensors, as well as electromechanical actuators that would provide movement for the robots.
“We have this big dream of the hardware compiler, where you can specify, ‘I want a robot that will play with my cat,’ or ‘I want a robot that will clean the floor,’ and from this high-level specification, you actually generate a working device,” says Daniela Rus. “So far, we have tackled some sub problems in the space, and one of the sub problems is this end-to-end system where you have a picture, and at the other end, you have an object that realizes that picture. And the same mathematical models and principles that we use in this pipeline we also use to create these folded electronics.”
To create such self-assembling devices it is necessary to accurately form the angles prior to heating a sheet of material so that the material bends and folds into the precise shapes required. This is achieved by sandwiching a sheet of polyvinyl chloride (PVC) between two films of a rigid polyester perforated with many slits of varying widths. When the material is heated in an oven, the PVC shrinks, and the slits pull closed and where the edges of the polyester push against each other, they deform the PVC. As a result, with precise control and planning, shapes of complex compound angles can potentially be created.
In a similar fashion, the folded electronic components are built using a polyester coated with aluminum. Given that these components required both geometric and electrical properties when heated and folded, these were created by hand, though it is envisioned that – with a great enough advance in the algorithms and techniques involved – these too will eventually be produced from 2D templates.
The practical upshot of all this research is that, one day, 3D objects will be generated from 2D templates that self-assemble when heated or subjected to another stimulus such as pressure or water, without the intervention of any other process (so called "4D printing"). The implications of this type of research go way beyond the ability to bake gingerbread men that get up and walk away when they’re done – it could form the basis of the next big revolution in manufacturing.
The MIT video below explains the process in further detail.