We've seen all kinds of crazy jumping robots, from humanoids to grasshoppers to soft and flexible spheres. But when you start making small robots, like seriously small robots (on the millimetre scale), you have to find new ways to get them to jump.
The Army Research Laboratory has teamed up with the University of Maryland to develop a couple clever ideas.
Pictured above is a 4mm long robot, complete with a power source, an integrated control system, and light sensors. To move, it relies on on the rapid conversion of stored chemical energy to gas in a chemical reaction, which is just a fancy way of saying either "rocket motor" or "controlled explosion." Underneath the robot is a small chip of nanoporous silicon that gets infused with a sodium perchlorate oxidiser, and when a current heats up the chip, it ignites, propelling the robot upward. Initial tests have yielded a jump height of about eight centimeters, which doesn't sound like much, but the robot is so small that it's still outjumping its own size by a factor of 20.
The other jumping bot that these researchers have come up with is a bit more traditional, using microfabricated elastomer springs to store up energy and release it all at once to make a jump. This method may be a bit less violent than the rocket-powered bot, but the spring robot depends on an external power source (a dude pushing the spring down with tweezers). With this human help (which will eventually replaced by micromotors to wind the spring up) it can jump really, really high, at about 80 times its own height. You can see both of these robots in action in the video below:
The next step for these robots is to tweak them to be able to jump more than once, and in the direction that you want them to go. Oh, and to figure out how to get them to land properly, and then do productive stuff once they return to Earth. For the chemical jumping robot, adding little nozzles to the chemical engine should solve the steering problem while also quadrupling its effective power by directing the thrust more efficiently. Stitching an array of about 100 of these engines together along the bottom of a microbot could allow for a whole series of jumps (and even jumps followed by mid-air rocket pulses to keep flying), ultimately resulting in a range of some 65 meters, which works out to be a staggering 16,000 times the length of the robot itself. Not bad at all.
Ultimately, the idea is that these bots will be fast and cheap to manufacture, easy to deploy, and expendable enough that it'll be possible to use swarms of them for things like surveillance and monitoring and terrorising your imagination.
"First Leaps Toward Jumping Microrobots" by Wayne A. Churaman, Aaron P. Gerratt, and Sarah Bergbreiter from the Army Research Laboratory and the University of Maryland Microrobotics Lab was presented this week at the 2011 International Conference on Intelligent Robots and Systems.
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