Yes. I need more limbs.

When we were talking to my daughter the other evening, she was struggling to manage a phone in one hand and a busy baby in the other, and I told her she just needed a third. Surprise! Science provides with a wearable robotic “third arm” that can punch through a wall. The “punch through a wall” feature seems particularly useful in the context of child care. Except, I’m sorry, the video makes it less than useful.

Nice gadget, but it requires one person to wear it, and a second person with two arms to control it remotely, effectively requiring four arms to enable three-armed activity, in which one of the three arms is rather clumsy. It’s going to require a better control mechanism, something with a neurological link to the wearer. As long as we’re doing that, why stop at three? Why not…eight? I am ready for my robotic exoskeleton that will let me climb walls and punch through walls and destroy walls any day now.

Oh, and do more efficient childcare, I guess.


  1. Matt Cramp says

    “As long as we’re doing that, why stop at three? Why not…eight?”

    Well, you’ll probably be stopped by Spider-Man, but presumably this is your plan to meet him

  2. leerudolph says

    It is, as we say, “proof of concept”. Or more precisely, “partial proof of concept” or perhaps merely “proof of partial concept”.

    Fourteen years ago (!), in an organizational session (for something that never ended up being organized) at the Philadelphia Robotics: Science and Systems meeting, there was a discussion of the social and architectural problem of doors (in the installed base of actually existing buildings of all kinds) that are difficult or impossible for differently-abled persons to open. (The ADA had been passed 16 years earlier.) It was definitely the sense of the meeting that something should be done, but what? Doors have many different designs, quite a few different purposes, and an enormous range of architectural and social settings.

    I held my tongue (being as it was only my second robotics conference, and I’m a mathematician with no engineering experience at all) during the meeting. Afterwards, as the room was emptying, I asked one of the conveners of the discussion whether it might be possible to design a robotic hand mounted on a single robotic arm that could be worn around the chest or waist of its user, just for the task of opening doors. I can’t remember what her objections were, but they were plentiful (and not too punishing to my eager ego) and convincing. It would appear that not much has changed (so she was probably right). It’s too bad.

  3. flange says

    A solution in search of a problem. From examples of using the device:
    1. Picking fruit from a tree: Instead of using the device to pick fruit, while the left hand holds the basket, use the left hand to pick fruit and attach the basket to a harness.
    2. Painting with a roller: The device strapped to the person doesn’t allow enough pressure on the roller to paint.
    3. Using power tools at work bench: The only thing the device can do is retrieve a power tool, not operate it. And the person has to look at the device and power tool.
    4. Sheet rock: The device doesn’t so much hammer at the wall, as flail at it.
    On the other hand, in 1990, I thought the internet was B.S. and would never be a useful thing. So, who knows?

  4. wzrd1 says

    Initially, I thought it was a gift from inventor heaven for folks slinging network cables. But, since there’s a pair of hands working the one clumsy hand, that’s a net loss.
    If I ever have another massive trunk of cables to run again and my drywall saw is at the other end of the building, I’ll just use what I did before under those conditions. Grab my Stanley stainless steel thermos and bash a fine round hole through the firewall, then seal it after the run is complete. A plus is, no synthetic chunk of plastic and metal to knock me off of the ladder.
    I’m quite good enough at doing that myself.

  5. stwriley says

    Actually, it looks like an extremely effective robotic arm…for a robot. Put that arm on a decent-sized robot and it could be very useful for doing dangerous tasks remotely (fire fighting, bomb disposal, etc.) Put it on a human and it’s about as silly a thing as I’ve seen in a while.

  6. jacksprocket says

    Biomechanics are already harnessing brain signals to control prostheses. I wonder if the brain could control an extra limb? Different, we never had one, but….? Soldering uncooperative cables and connectors, I always fancied being like the Hindu goddess Durga, with her many arms… forewarned, after all, is four- armed.

  7. leerudolph says

    I just looked more closely at the picture (haven’t played the video, won’t). It’s a fucking THREE DEGREES OF FREEDOM robotic arm! For pity’s sake, the bucket on the electric company’s truck has 6 degrees of freedom and it’s very impressive to see workers using it to maneuver around and about, cutting branches, stringing lines, etc. etc. A human arm, with a spherical joint (3DOF) at the shoulder and a nice selection of revolute joints (2DOF apiece) at the rest of the joints, has dozens of degrees of freedom. If you’re not using your robotic arm in a hostile environment (like inside a hood in a chemistry laboratory, or on a space walk or something), why should you use it at all at the expense of having to do without all the freedom of motion a human arm-and-hand has? Motion-planning (theoretical and practical) for a 3DOF robotic arm is solved. Is this thing in the video a science-fair project or something like that??? GRRRH.

  8. says

    Doc Oc only had 4 extra arms and didn’t fare well against spidey. 8 on the other hand. One catch though; given your liking of both octopus and spiders won’t you be conflicted if he turns up to do battle?

  9. blf says

    The mildly deranged penguin points out a prehensile tail would not only be much useful, but also a lot cooler.

  10. leerudolph says

    Me, @09: a revolute joint has 1, not 2, degrees of freedom. Sorry for my idiocy.