February 17, 2012, 12:13 PM —
Counter-intuitively, a Harvard engineering lab specializing in research on ultra-small robots has adapted cutting-(paper's)edge technology from origami and children's pop-up books into a process designed to make it possible to mass-produce tiny flying robots at a cost that might make it practical to manufacture more than one.
The process developed at the Harvard Microrobotics Laboratory is necessary to keep costs and logistics under control as the lab moves into experiments involving hives full of its RoboBee flying microbot, rather than just one or two at a time.
The Microrobotics Lab specializes in developing unmanned aerial vehicles (UAVs) designed to operate in much the same way as Predator spy drones shrunk down to the size of a bug.
RoboBee is one of a number of engineering research projects sponsored by defense contractor BAE Systems, which is working for the U.S. military to develop spy drones too small to be detected easily but capable enough to be piloted into buildings, training camps and other areas inaccessible to aircraft the size of a sedan.
Harvard researchers project the robot bee can also be used to pollinate fields of crops (putting real bees out of jobs) as well as civilian surveillance missions such as search-and-rescue, traffic monitoring and exploration of hazardous environments.
The problem with developing micro-robots isn't just the size of the whole unit; it's all the things that go into making it possible and practical. In addition to the trick of designing a semi-autonomous bug-sized robot, researchers have to design components small enough that their size, weight and capacity don't pin the RoboBee to the ground or shorten its flying range so much that it would be useless as either a drone or a spy.
So the Harvard lab spends as much time developing new batteries, smart sensors and better programming that can run on processors small and light enough not to overburden a machine with about the same lifting capacity as a real bee, according to lab publicity documents.
They also have to find materials and manufacturing techniques that don't make producing each microrobot so slow and expensive that they waste all their time and grant money.
The manufacturing process involves pressing 18 layers of pre-cut carbon fiber into a single joined structure that expands when you pull on it until the whole robot unfolds.
The RoboBee fold-out prototype is about the size of a quarter but weighs one-sixty-third as much. It has 137 joints, 22 of which fold, and 52 spots on which circuitry or components can be welded.
The layered manufacturing process is similar to the way circuit boards are made: each layer is printed, cut or folded with a separate set of circuits or components that all connect neatly when the layers are all pressed together into a single sheet at the end of the process.
Since the technology is the same as that used by circuit-board makers, machinery for making the fold-out robo-bugs is cheap and plentiful, cutting costs down even further compared to hand assembly, which had been the only other option.
Automating the technique "takes what is a craft, an artisanal process, and transforms it for automated mass production," according to graduate student Pratheev Sreetharan, who co-developed the technique.
It also makes it possible to design a whole machine with integrated electronics, manufacture them flat and make them work as fully three-dimensional objects just by pulling up on the stacked disks until the robot pops into shape, according to Rob Wood, an Associate Professor of Electrical Engineering at SEAS and a Core Faculty Member at the Wyss Institute for Biologically Inspired Engineering at Harvard.
The technique applies to many types of small device, not just RoboBees.
"We can generate full systems in any three-dimensional shape," Wood says. "We've also demonstrated that we can create self-assembling devices by including pre-stressed materials."
If a new bee needs more components, more features, it's only necessary to laser-cut a few additional layers of Kevlar, carbon-fiber, polymers, ceramics or any other material, then slip them into the correct order in the stack of layered, pre-cut parts.
The precision of the design, production and assembly of components is so precise, the lab can literally not measure how tight the tolerances are on its final product,
"The alignment is now better than we can currently measure," Sreetharan, said."I've verified it to better than 5 microns everywhere, and we've gone from a 15% yield to—well, I don't think I've ever had a failure."
Though the process is specific to the RoboBee, it and its (literally) unmeasurably fine tolerances for component manufacture can be applied to almost any other tiny machine as well
The full process will be published in the March issue of the Journal of Micromechanics and Microengineering.
The U.S. Army Research Laboratory and National Science Foundation both contributed grant money to fund the RoboBee program, so they'd get first dibs on any end product.
The Harvard Office of Technology Development is also looking for a way to commercialize the RoboBee.
So it's possible that within a relatively few years you'll be able to buy a flat disk packaged in paper like a book of stamps from a RoboVending machine and pull up on a string to unfold an internally powered, fully functioning remote-controlled flying robot.
Who cares if there would be an actual, practical use for it? Get one to look under the couch for the remote or harass the cat. If they're as cheap to make and distribute as they should be using this approach, it would be easy to justify buying one just for its cool-gadget rating (10+) rather than its practicality (rating: 3ish).
My only hesitation is from the horror-movie images that spring to mind when Wood and Sreetharan talk about experimenting with "swarms" of RoboBees.
But as long as Harvard is sure the RoboBees couldn't find nourishment or energy by, say, swarming over and devouring their owners, I'm sure I could be convinced to give the bees a try.
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Harvard Microrobotics Laboratory
