This is the third installment in what could be billed the "building series."  The first two articles focused on rather involved fabrication techniques for larger robots; this time, I'd like to look at two more-accessible techniques for building miniature robots that I learned about at IROS 2009.  The first technique, by Jessica Rajkowski and advisor Sarah Bergbreiter (et. al.) from University of Maryland, is a relatively new method employing multi-step photolithography via inkjet printed masks to build small polymer robots such as inchworms and grippers that are actuated by shape memory alloys (SMAs).  The second technique examined is a bit more mature.  Called "Smart Composite Microstructures" (SCM) and hailing from UC Berkeley's Biomimetic Millisystems Lab, this technique is used to build inexpensive, resilient, folded composite (cardboard, carbon fiber, fiberglass) prototypes with polymer hinges.  Read on for details and videos.

I'm a huge fan of so-called micro robots -- those with cm length scales, thus μ m³.  I've posted about numerous micro robots before, including the amazing Alice micro robot swarms from EPFL, and I am a long-time micro and nano autonomous sumo robot advocate (see RoboGames).  Perhaps that is why I'm so excited about the SwarmRobot.org open hardware micro-robot swarm, developed by the University of Stuttgart and the University of Karlsruhe.  All of the hardware and software is open (in the GPL sense), including parts lists, circuit board and chassis designs, and software.  With a stated goal to produce sub-€100 robots, I'd really like to see this take off.  Combined with a wireless power surface, a micro-robot in perpetual motion would make a great desk ornament!

It appears the I-Swarm robot project has produced some fully-integrated and apparently functional micro robots -- almost four years after we saw the initial conceptual videos appear online.  What makes these robots so impressive is the level of integration; they possess a micro-step locomotion mechanism, a solar cell, custom IR communication modules, and an ASIC (custom silicon circuitry) all in a very compact package.  I've quite impressed by the pictures and videos (embedded below).  Since I-SWARM stands for "Intelligent Small-World Autonomous Robots for Micro-manipulation", I'm a bit perplexed by the lack of manipulation capabilities.  They do have a small piezoelectric-driven cantilever arm in the front, but it currently doesn't seem as capable as AFM tips employed by the MiCRoN project's micro robots.  Perhaps, as the PhysOrg article notes, they just need additional funding -- appropriate for such quality engineering and top-notch research.

Alice is a micro robot development by Gilles Caprari at the Autonomous Systems Lab at Ecole Polytechnique Federale De Lausanne, or EPFL -- a University in Switzerland.   In a sense, Alice was the culmination of 8 years' worth of research efforts spanning a number of micro robots, including Smoovy, Jemmy, and Inchy.  From early on, Alice was designed to be a small, inexpensive, and simply-constructed autonomous micro robot.  Alice was quite an impressive robot, particularly when one considers the numerous extension modules developed and the large swarms that were constructed (videos showing ~90 robots operating simultaneously are shown below).  Alice measures in at just under  1 cubic inch (22mm x 21mm x 20mm or 9.24 cm³).   Fortunately, this robot sports a very open design -- documented both on the Alice homepage and in numerous publications (of which Gilles' PhD dissertation is probably the most illuminating).

Inchy is a micro robot based on the (now discontinued?) smoovy motors.  This robot comes from the Microprocessor Systems Lab at Ecole Polytechnique Federale De Lausanne, or EPFL -- a University in Switzerland -- where numerous micro robots (such as Jemmy, Smoovy, and Alice) were developed.  The builders of this robot actually went on to found Didel, a provider of micro-robot components (such as the motors for Pico, another micro robot). Unfortunately, this robot lacks(detailed) technical specifications.  Inchy measures in at 1 in³ (or about 16.4 cm³).

Jemmy is a micro robot based on the (now discontinued?) smoovy motors.  This robot comes from the Microprocessor Systems Lab at Ecole Polytechnique Federale De Lausanne, or EPFL -- a University in Switzerland -- where numerous micro robots (such as Smoovy, Inchy, and Alice) were developed.  The builders of this robot actually went on to found Didel, a provider of micro-robot components (such as the motors for Pico, another micro robot). Unfortunately, this robot lacks (detailed) technical specifications, but it is very aesthetically pleasing and has a phenomenal mechanical design (with custom-machined gears).  Jemmy measures in at 1 cm³ and appears to be tethered.

This nameless robot has been dubbed "Smoovy", as it was based on the (now discontinued?) smoovy motors.  This robot comes from the Microprocessor Systems Lab at Ecole Polytechnique Federale De Lausanne, or EPFL -- a University in Switzerland -- where numerous micro robots (such as Jemmy, Inchy, and Alice) were developed. The builders of this robot actually went on to found Didel, a provider of micro-robot components (such as the motors for Pico, another micro robot). Unfortunately, this robot lacks (detailed) technical specifications, but it is very aesthetically pleasing and has a phenomenal mechanical design with custom-machined gears.  Smoovy measures in at 1 cm³ and appears to be tethered.

Pico is an impressive hobbyist robot.  It measures in at 2 cm³ (12.5mm per side) and features a laser-cut chassis, two Didel motors (MK04S-24 driving worm gears), an A3901 stepper motor driver, and an ATtiny44 microcontroller. With a run-time of 15 minutes off a 10mAh Li-Poly battery (approx 3.7V), that equates to a power consumption of about 140 mW. I suppose the large power consumption is to be expected, given that the Didel motors employed can use as much as 100mA at 3V!

There has been a lot of discussion recently by Intel's CTO (Justin Rattner) about some really compelling future technologies: wireless power and programmable matter (made of catoms).  Of course, the programmable matter (catoms) he is discussing are basically robots operating as a swarm.  Wouldn't it be neat to see the swarms actually powered wirelessly?  While Intel has thus far worked on the two technologies disjointly, work presented by myself at ICRA 2008 is addressing the intersection -- wirelessly powering a swarm of robots (publication here).