I swarm, you swarm, we all swarm for millimeter-sized autonomous robots

If you thought the cyborg moth had cargo problems, consider the millimeter-sized I-SWARM microbot presented at ISSCC by researchers from the University of Barcelona, a ladybug-sized piece of machinery that has to lug around its own control electronics, communication electronics, capacitors and little tiny solar panels. It weighs 70 mg which is about the weight of a standard multivitamin.

First, an important question: why are we making fake ants?

Many applications would be good for tiny robot swarms, some of which were enumerated back in October on our sister blog, Automaton.

First, if you send a swarm of ten thousand to do some task, and one thousand die, chances are your project will be unaffected, so the system is inured from failure by redundancy.

Second, you can do things that are possible only through teamwork. Astrobiologists love the idea of swarming robots because ideally, they could build themselves into a bridge, or build themselves into a ladder or a pile, anything the task required.

Finally, if you can make them on the cheap and out of silicon, you'll be able to fab them like microchips, which means that you might end up with similarly small per-unit costs. Pretty good for an autonomous robot.

But you can't build one of these little suckers with commercial off the shelf electronics, which is why Raimon Casanova Mohr created the first system-on-chip specifically for an autonomous mobile microbot. The microbot can be optically programmed kind of the way you would beam a business card to a Blackberry. It includes all necessary electronics except for 3 capacitors: Essentially, like tiny ants, these I-SWARMS can move autonomously, process limited "sensory" data, make decisions based upon that data, and then communicate amongst themselves to do whatever it is that they are programmed to do. Their programmable behavior can be changed on the fly.

This is part of an EU-funded project though it's unclear which. Automaton has it as one of two sister projects, both funded under EU's Seventh Framework Programme spanning from January 2008 to 2013. An article from the UK Register reports that it was funded earlier by the EU Information Society Technologies (IST) Sixth Framework Programme (starting in 2003).

Mohr showed pictures of the setup in his lab: the swarm's "work area" is a space about the size of a piece of letter paper enclosed in plexiglass like a penalty box. It's uniformly illuminated by a high intensity lamp, which powers a 3.9 square millimeter solar cell array on the I-SWARM, which in turn generates 1 mW for the system-on-chip and half of that for its "body:" 3 piezoelectric legs driven by square waveforms at its resonance frequency, 32.86 kHz. The legs can go forward, backward or spin. The system on chip is 2.6 mm by 2.6 mm, about the size of a sunflower seed. Most of these components, including two little capacitors, are assembled on a flexible printed circuit board that does double duty as the bug's backbone. But the leftovers that are stored in the capacitors aren't even enough to retain the bug's programming, so it has to be reprogrammed every time it starts. The process takes around 45 minutes.

The programming is done by an IR projector that sits next to the HI-lamp.

The I-SWARM has an optical chip for short-range IR communication with 4 pairs of LEDs/photodiodes, one for each side of the chip. The information is

sent by LED, and received by photodiode. This is how it positions itself relative to its herd, and to the projector. The IR projector also confirms the exact position of each robot over the working area.

The robots are very cute--after the ISSCC presentation, I overheard one engineer referring to them as "little animals" which I found telling. Sadly, there was no video, because apparently the solar PV panels were on the fritz. But it's not the end of these guys. We're one year into the second phase, and I'm interested to see what awaits us in 2013. Meanwhile, check out Automaton for the old videos.


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