Micro Robot Disregards Gears, Embraces Explosions

Researchers at Cornell University have developed a tiny, proof of concept robot that moves its four limbs by rapidly igniting a combination of methane and oxygen inside flexible joints.

The device can’t do much more than blow each limb outward with a varying amount of force, but that’s enough to be able to steer and move the little unit. It has enough power to make some very impressive jumps. The ability to navigate even with such limited actuators is reminiscent of hopped-up bristebots.

Electronic control of combustions in the joints allows for up to 100 explosions per second, which is enough force to do useful work. The prototype is only 29 millimeters long and weighs only 1.6 grams, but it can jump up to 56 centimeters and move at almost 17 centimeters per second.

The prototype is tethered, so those numbers don’t include having to carry its own power or fuel supply, but as a proof of concept it’s pretty interesting. Reportedly a downside is that the process is rather noisy, which we suppose isn’t surprising.

Want to see it in action? Watch the video (embedded below) to get an idea of what it’s capable of. More details are available from the research paper, as well.

18 thoughts on “Micro Robot Disregards Gears, Embraces Explosions

  1. The US Army’s short range anti-tank missile the M47 Dragon (obsolete) used to “steer” like this. The body spun in fight and small motors(?) fired in short bursts precisely timed to kick the missile back on course. It was literally an “bang bang” controller! Never saw one but heard from people who did that the herky jerky flight path was very distinct and unique. I found a short clip on YouTube, where someone colorized the puffs of each kick


    1. That’s just an ordinary pulse-modulated rocket engine, those are ubiquitous. Practically all small pressure-fed liquid-fueled thrusters in spaceflight (probe landing thrusters, RCS, etc) are pulse-width modulated by a fast valve capable of firing hundreds of times per second, because it’s easier and more effective than an elaborate throttling mechanism that is needed on larger engines.

      The thruster in the article is more interesting because it works in an enclosed flexible chamber. It’s not a rocket engine, it pushes off the surface.

      1. While I’d agree that it’s conceptually like more traditional RCS thrusters in space craft, as far as I know, this particular system is a bit unique. First of all, there isn’t a single motor providing thrust to be pulsed, and the rocket engines aren’t liquid fueled. There are 30 each tiny solid-rocket motors arranged in 3 banks of 10 arrayed along the side of the missile, each row of ten engines positioned 45 degrees from the next (so these rocket engines only encompass half of the perimeter). Each rocket points out and down, so it provides both thrust and sideways “steering”. It seems they were fired in pairs, but it’s not obvious how such pairing was done. Seems that each pair was fired about once a second (or 500 ms?), each kick was very short, and generated 1.2 kN (265 lbs).

        BTW, I didn’t know this off the top of my head, I had to search around online. While searching, I also learned that this missile was not very popular with the soldiers. I’m not sure whether that’s because of the “bang bang” nature of its propulsion / guidance, or some other factor.

        Engine: https://www.armedconflicts.com/attachments/12663/Drag3.jpg
        Cutaway: https://i.imgur.com/upfnDW2.jpg

    2. Oxygen using fartbot would not be open access. Points for gerontology first soft robot work, looking forward to robots made of spermidine and inflammatory compounds motivating shambling biofilms to do useful work eating (model insect) brains.

  2. So people want away from fossile fuels.
    Oil industry gives scientist money (of corse and tax money) to developed new fossile burning machines. Sometimes scientist need a cozy hug from train.

    1. methane is something like 20-25x stronger of a greenhouse gas than CO2, and we have numerous natural sources of methane that would still exist with zero fossil fuel sourced methane (cow farts, human farts, leaks due to geologic events, w/e) https://www.epa.gov/gmi/importance-methane

      It’s likely that this could be modified to use pure hydrogen or some other gas. Being able to run on that sort of waste methane to convert into CO2 and then use the CO2 for other processes.

      We can eliminate fossil fuels and restore balance to greenhouse gas emissions more easily, but that doesn’t mean eliminating the burning of all hydrocarbons ever.

  3. I really HATE these micro robots claiming they can be used in “search and rescue”
    Just showcase your graduation thesis as micro explosive actuators, without the justification of it’s existence.
    The maker did a great job finding the right materials and techniques and making them working in a fun new way.
    But let’s be honest it is terribly unpractical for that purpose.
    In big disasters we have dogs and camera’s to find the peoples but we need bulldozers and caterpillar to take control of the situation quickly.

    Problems with this:
    – It takes forever to get to a certain place, if it can get there in the first place.
    Yes it can jump but it is completely random where it lands, so control is 0.
    – Load capacity is next to nothing.
    Yes it can carry 20x it’s own weight, 20gram without controls, battery, gas-tank, camera. leaving nothing for important rescue stuff.
    – Life expectancy.
    How make explosion can it withstand, before destroying itself. In search and rescue you can’t really waist time fixing you equipment.

    Last thing I want to see when I’m buried in a collapsed building is a comically jumping robotic frog passing by.
    Maybe it can carry a final cigarette and light it for me when it reaches me.

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