Robot Jellyfish Fueled By Hydrogen From The Water Around It

RoboJelly is certainly not what we’re used to seeing when it comes to robots. Instead of a cold metallic skeleton, this softie is modeled after jellyfish which have no bones. But that’s not the only thing that’s unusual about it. This robot also doesn’t carry its own power source. It gets the energy needed for locomotion from the water around it.

Artificial muscles are what give this the movement seen in the clip after the break. These muscles react to heat, and that heat is produced through a chemical reaction. The construction method starts with the muscle material, which is then covered in carbon nanotubes, and finally coated with black platinum dust. Sounds a bit like witchcraft, huh (Eye of newt, dragon heart string, etc.)? We certainly don’t have the chemistry background to understand how this all works. But we are impressed. So far it doesn’t have the ability to change direction, the flexing of all of the muscle material happens at the same time. But the next step in their research will be finding a way to route the “fuel” to give it some direction.

Edit – Looks like it is fueled externally. The actual study is here, but you need to log in to download it.

This brings another jellyfish-inspired robot to mind. Check out FESTO’s offering which flies through the air with the greatest of ease.


[via Reddit]

26 thoughts on “Robot Jellyfish Fueled By Hydrogen From The Water Around It

  1. Summary and linked article are bullshit… it runs on an external source of hydrogen gas, not water (free energy anyone? Bueller???)

    You’re certainly right about not having the high-school chemistry background necessary to understand this.

  2. Read closely and you’ll see that the current version uses an _external_ source of hydrogen which is “injected at the top”. The robojelly does NOT extract hydrogen from the water.

    That said, it’s still cool and still has lots of potential, but it is not a miniaturized H2O splitter…

    1. Speaking from my memory, water still contains free hydrogen and hydroxide ions regardless of its PH . . . If you have a way of attracting the hydrogen and or hydroxide ions you have a source of energy.

      1. “water still contains free hydrogen and hydroxide ions regardless of its pH”
        True but the ratio of the H+ and OH- concentrations are inversely proportional such that [H+] x [OH-] = 10e-14

        where [] denotes concentration. At neutral pH, ie 7, the concentrations are 10e-7 molar for both H+ and OH-. At such low concentrations, the reaction rates are very small. You can lower the pH to make [H+] bigger but then [OH-] falls visa versa if you raise the pH. Reaction rates are usually proportional to the product of the substrate concentrations.

        Also from a thermodynamic standpoint, you can’t expect the spontaneous dissociation to H+ and OH- to give useful energy. If it did, what would keep oceans and lakes from spontaneously exploding?

  3. i skimmed through the actual paper–hydrogen and oxygen are injected from the top. the interesting thing is that they coated nitinol wires (you know, muscle wire that flexes when you apply a current and heat it up?) with platinum catalyst with a carbon nanotube support matrix probably to maintain high surface area, keep the particles thermally close to the nitinol wire, and hold the particles in place. Basically, the platinum catalyzes the reaction between hydrogen and oxygen, and uses the heat to heat up the muscle wire and move. it’s a somewhat interesting general concept: muscle actuators that don’t use electricity but use the gas around it to actuate.

    1. Well, not to be obnoxious, but this is technically no different from other sma wire, because sma is always actuated by heat. However, in this case the heat is thermochemically generated, not electrically. I agree that this is a very interesting idea, although certainly not very controllable.

  4. Doesn’t need to vary the pulses – it just needs to have a shifting weight inside that can tilt it in the direction it wants to go.. then just vary the interval of fluctuations to decide if you go up or down or stay at “roughly” the same level.

  5. Make that jelly extract power from the water it is in, and I’ll be impressed. Though I have watched before in discovery channel that some jellies had algae on them that gives the jelly it’s “food/energy” so…… why not use solar panels instead? :O

        1. Medusa jellyfish.

          Few corals live below 100m in pristine tropical waters and the PV cells we make are no where near as efficient as zooxanthellae in converting sunlight to energy. Since most scientific equipment deployed in the ocean is seen as expendable it makes more sense to use lithium cells unless it’s 100% a surface deployment. Heck even most of the worlds military submarines are diesel-electrics.

          Most light is filtered out by 250m, nevermind any effects from turbidity or angle of incidence.

          A neat PoC and certainly worth funding the research, but far from deployable.

    1. Exactly. Like calling a pneumatic sander a robot because it vibrates across the table.

      The muscles are interesting though. Now all they need is a simple method of to producing and evacuating hydrogen on demand.

  6. From the link:

    “however, the potential can be seen in this video where the robot is powered by electricity.”

    Unless I am mistaken the jellyfish is not being at all powered as described and is, in fact, being powered by an external electricity source in the video. Someone correct me if I am wrong.

  7. Regardless of the power source in the video the concept still works. Most robots start off tethered with an external power source … look at the first testing videos of big dog.

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