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Science Technology

Ankle Exoskeleton Takes a Load Off Calf Muscles To Boost Walking Efficiency 128

Posted by samzenpus from the stepping-easy dept.
Zothecula writes We might have started off in the water, but humans have evolved to be extremely efficient walkers, with a walk in the park being, well, a walk in the park. Human locomotion is so efficient that many wondered whether it was possible to reduce the energy cost of walking without the use of an external energy source. Now researchers at Carnegie Mellon and North Carolina State have provided an answer in the affirmative with the development of an unpowered ankle exoskeleton."
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Ankle Exoskeleton Takes a Load Off Calf Muscles To Boost Walking Efficiency More

Ankle Exoskeleton Takes a Load Off Calf Muscles To Boost Walking Efficiency

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  • ... so you're all set. Although, no braces on your arms, though, so you're going to have to rely on the old human strength to keep a grip on the device and, by extension, me. So do make sure to keep a grip on me.

    Also a note: no braces on your spine, either, so don't land on that. Or your head, no braces there. That could--that could split like a melon from this height. [nervous laugh] So do definitely focus on landing with your legs.

  • Humans started out in the water?

    I mean, life started out in the water, sure, but there was a lot between the first creatures to leave the sea and humans.

    Unless you're referencing that theory that humans evolved near the ocean, hence our relative hairlessness and whatnot. I thought that theory was out of favor.

  • Heh.
    This must be some new kind of energy ...
    Every system you want to gain energy from has to be loaded with energy first. Both isn't possible without losing energy, at least in our universe which means any additional device on the human body makes the body lose more energy.

    And probably completely unrelated:
    The original article appeared on Nature [nature.com] on April 1st.

    • Heh. This must be some new kind of energy ...

      It's not adding energy, it's avoiding some of the loss. A chair does a similar thing. By using that you expend less energy than by having to maintain your balance by standing.

      • Re: (Score:1)

        by Longjmp ( 632577 )
        *chuckle*
        You should demand your money back from your school - or rather your physics teacher ;)
        Also it might help to read my post to the end.

        • Gravitational potential energy converted to elastic potential energy which is then reversed. Heat is generated during the process, but probably not as much heat from the normal walking process.

          Your argument about adding weight to a system causing it to use more energy would make sense if you were always going uphill. If you are still at ground level that probably isn't true. The Prius is heavier than a normal car(additional weight of battery and electric motor), but it still ends up being more fuel efficien

          • Have you ever climbed a mountain, or gone backpacking? If you could go 7% farther in a day for the same energy input, or carry 7% more weight, it would be damn useful.

            Not everything is about exercise, sometimes you want to reduce your energy usage.

    • Re:"Unpowered" Energy ;) (Score:4, Interesting)

      by Anubis IV ( 1279820 ) on Friday April 03, 2015 @04:54AM (#49396599)

      Don't be obtuse. It's clear that what they're getting at is that it isn't externally powered when they say it's "unpowered".

      Moreover, you've failed to consider how different efficiencies can affect the situation (i.e. the real world is not a frictionless vacuum). Yes, moving more mass means requiring more energy...output energy. But what we're concerned with here are inputs, since that's what we're expending.

      Just to drive home the importance of the distinction between inputs and outputs (and also to toss in an obligatory car analogy), consider the Tesla Model S. It weighs about 50% more than a Toyota Camry, which means it'll take a greater energy output to move than the Camry. That said, the Camry's engine is only about 1/3 the efficiency of the Tesla's, which means that despite its lighter weight you'll still have to put more energy into it than the Tesla to get it to move the same distance.

      The same applies here. Yes, adding an extra mechanism adds more weight, which means that the necessary energy output is greater. That said, your calf is inefficient at locking up during the downward part of your step, whereas a mechanical clutch is quite efficient at locking up, so by relying on simple machines to divert those forces to the clutch instead of your calf, you can reduce your dependency on an inefficient system (i.e. your calf), thus reducing the amount of input energy necessary, to the tune of 7%.

      Or, hey, it's impossible. Because efficiency isn't a thing. How do you breathe in a frictionless vacuum, anyway? :P

      • Also: muscles just aren't amazing as springs.
        They're ok, but not as good as proper springs (ask the IAAF and Oscar Pistorius -- Philosoraptor: "Maybe we should give the elderly these blades instead of lower legs? Will old people lead the cybernetic revolution?").

        It's like comparing a car with regenerative braking to one without (yes, also a car analogy). It's easy to see that the energetic cost of any added weight is easily offset by the reduced loss of energy to friction.

        • The elderly and partially disabled need leg supports that keep you from falling. Occasionally my right leg gives out. I go to take a step and BOOM, I'm on the ground. It happens often enough my reflex is to put my hands to my chest and roll to land on my right shoulder. It's hard to get some exercise and yard work done when you spend a fair amount of time inspecting your lawn at eye level.
  • With a pair of these, I'll be able to get my fat ass up and grab some more Cheetos without getting out of breath!
  • The Olympic Committee, professional sports of all kinds, scholastic sports, athletics, and so on. Will these be allowed? Will they be disallowed? Is there already rules in the books that cover something like this, or will there have to be a flood of new rules in every sports organization to cover unpowered exoskeletons of all kinds?

    • Unless your sport is casual walking it won't.

    • This has basically already happened.

      http://en.wikipedia.org/wiki/O... [wikipedia.org]

      Oscar was a double amputee, and a research subject for some fascinating "blade" prosthetic legs who won olympic gold medals for running. Some of the creators of the devices made the same kind of elementary mechanical mistake as some of the posters here: There is a fascinating documentary on Oscar's case, where one of the leg designers said "If they're unp

    • Remember those incredibly flexible poles used for pole-vaulting? The ones that bent like crazy, then straightened to boost the pole-vaulter to unheard-of heights.
  • This invention still does not counter the rise and fall of the upper body that occurs with each step, therefore this cannot address that lost and wasted energy. That's what makes cycling so efficient compared with walking, and presumably compared with this invention..

    • This invention still does not counter the rise and fall of the upper body that occurs with each step, therefore this cannot address that lost and wasted energy.

      The motion of the center of mass is not where the metabolic power of walking goes, any more than the rise and fall of the mass of a pendulum requires external power. That's kind of the point of this: the potential energy of the high center of mass converts to kinetic energy at the low center of mass like a pendulum, and elastic mechanisms in your tendons let you 'bounce' off the ground. This device reduces the muscular effort required to bounce.

      Most of the energy cost lies in lifting each leg and swinging

      • Re: (Score:2)

        by dfghjk ( 711126 )

        I'm impressed by the stupidity displayed in this comment.

        If what you say is actually "the point of this", then you've proven your very first claim false. If the device is designed to recover lost energy in the motion of the center of mass, then there must be lost energy there unlike the motion of a pendulum. It's not a "bounce" if it requires "muscular energy" for its movement.

        On a bicycle you absolutely have to move your leg up and forward with each pedal stroke. It cannot get there any other way. Now,

        • On a bicycle you absolutely have to move your leg up and forward with each pedal stroke. It cannot get there any other way. Now, the leg may be moved there by the effort of the other leg or it may not, but either way the energy comes from you and nowhere else.

          Ooh, here's an idea to improve bicycles forever! Your gluten are really good at pushing down but you're right, pulling up and over is a weakness for many people. What if - I know its crazy but stay with me here - what if we connected the two pedals so that instead of being independent, a tiny amount of the force that you push down with your big muscle groups could be used to help the other leg get into position for the next stroke?

          I'mma gonna patent this right now. It'll make million$!

      • A pendulum is powered by the rotational energy of the earth in its orbit around the sun. It has the largest external power source in the world.

        • Say what? No.

          A pendulum is powered by the person who raised it for the first swing - after that its energy is cyclically transformed from gravitational potential energy to kinetic energy and back again. Perhaps you're thinking of the giant pendulums whose swinging plane slowly rotates - that rotation is indeed powered by the motion of the Earth (or more accurately, demonstrates the rotation of the Earth under the pendulum), but the energy of the swinging itself is all imparted when the pendulum is first r

          • Even worse: 'orbit around the sun'.

            I think the GP qualifies as 'not even wrong'.

          • Pendulums swing forever. Have you not seen a pendulum? They get momentum from the rotation of the earth. There's a pendulum that has been swinging since 1855; that doesn't just happen by magic.

            • Only in a frictionless vacuum so that there's no energy loss. Or if there's an external energy source powering it (such as the hanging weights on an old-fashioned pendulum clock.) I have seen many pendulums, and they all slow down over time.

              There are indeed some Foucault pendulums that have been on display for decades maybe even centuries, but they require someone to come along and boost their swing periodically - they don't magically suck power out of the motion of the Earth, they just demonstrate its ro

              • The original discussion was on the claim that a pendulum swings forever without input energy, which is only true for certain pendulums, and so these are the pendulums being discussed.

                The pendulum is carried by the rotation of the Earth; it's not in a fixed location, swinging in the same spot while the Earth moves under it. It changes its trajectory because the Earth passes some of its momentum to the pendulum.

                Am I going to have to get Randall Monroe on this?

                • No, the original discussion was relating the rise and fall of a person's center of mass to that of a pendulum, where no external energy is (necessarily) needed - nothing was said about pendulums swinging forever until you made your ridiculous claim.

                  There may be some small amount of momentum transfer between pendulum and planet (rotation only though, nothing that would impact its orbit around the sun), which is why I said it *might* be possible to construct a "perpetual" pendulum if you specifically attempte

                    • Yes - nothing there about perpetual motion, simply a reference to pendulum motion - you don't have to add energy on every swing, it will continue to to rise and fall without any external power source (at least until entropy robs it of it's momentum - but if we have to state that explicitly in *every* conversation it's going to get really tedious. Should we add "under the influence of gravity" as well?)

                    • You're telling me that the statement was that a center of mass continues to move forever when walking and requires no energy to keep it moving? That a person with more weight strapped to him--50 pounds strapped to his chest--won't have to work any harder to walk down the street than a person who has nothing attached? That's what the statement indicated?

                      ... it did apparently indicate that yes; just like it indicated that a pendulum, once set in motion, continues to rise and fall with no external power.

                    • No, that was *their* claim - inaccurate in my opinion because humans *don't* have particularly elastic tendons. Kangaroos though *do*, and are by far the most efficient running animals on the planet. Despite their dramatic vertical motion they're nearly as efficient as wheeled vehicles.

                      Right, no external energy is required to keep a pendulum moving, for a while - entropy will eventually win, obviously, but you don't have to introduce any new energy to get the pendulum to climb back up the opposite side of

                    • No energy is required to keep ME moving--for a while. I have momentum when I take ONE STEP.

                      You're making a distinction between "it rolls for a while once you push it" and "it only rolls like, half an inch." In both of these situations, the thing stops; it requires additional energy to keep moving. To state that a pendulum doesn't need additional energy to keep moving is to state that a pendulum will carry its full swing FOREVER, not FOR A LITTLE WHILE or FOR A THOUSAND YEARS BEFORE FINALLY WEARING DOW

                    • You're being pedantic. NOTHING ANYWERE moves forever, not even orbital systems, though they slow down much slower thanks to the near-vacuum they operate in.

                      The point is, there is no *inherent* reason in an *idealized* system why the cyclic motion in walking (or pendulums) needs to consume energy. So long as energy is being lost, there's the potential to reduce those losses to get arbitrarily close to zero. Contrast that to lifting a box, wherein the input energy has an absolute minimum equivalent to the

    • It's funny, too: humans are so efficient walking that we don't know if we can make them walk any more efficiently, but we do know that they use as much energy to walk 1 mile as they use to bicycle 7 miles.

      • Re: (Score:2)

        by mark-t ( 151149 )
        Cycling isn't walking. It might be unpowered (save for human muscles), but its definitely not walking... if you are going to argue that moving around in this unpowered exoskeleton isn't really walking either, then you might have a point.
        • Cycling is unpowered. Walking is unpowered. Both use the same human muscle system and human fuel system, but one accomplishes locomotion with 1/7 as much energy. Walking is obviously very inefficient, and to claim humans are so efficient at walking that we don't know if we can make them any more efficient is ludicrous; there is obviously a lot of loss in the system to look for.

          • Re: (Score:2)

            by mark-t ( 151149 )

            Of course there are more efficient systems for getting around.... but is there much room for improvement for the practice of walking itself?

            Walking may admittedly be overall quite inefficient as a means of motion when you compare it to something like cycling, but how humans walk still might be as about efficient as the practice of walking itself can still physically get.

            • but is there much room for improvement for the practice of walking itself?

              Of course there is. If it's less efficient than cycling, then energy is lost somewhere in the system. Walking carries a stop effect that brings a mass to rest by dissipating the motion energy from heat; it carries friction and deformation effects from elastic pressure on joints and tendons; it carries loss in the form of inelastic muscle movements, pulling one way and then the other; it even carries a loss from fighting against gravity to lift the leg, and then not storing the gravitational potential whe

              • Re: (Score:2)

                by mark-t ( 151149 )

                Of course there is. If it's less efficient than cycling, then energy is lost somewhere in the system

                Its less efficient than cycling, as was pointed out above, but again.... cycling isn't walking. I'm not arguing that there are much more energy efficient means of unpowered locomotion, the article merely suggests that the way that humans have evolved to walk may very well be nearly as efficient as *walking* can physically get.

                The fact that there provably exists far more efficient modes of externally unp

                • It's like suggesting that you should be able to get just as much energy out of a coal furnace as a nuclear one of the same size.

                  There's more actual energy in a nuclear pile than in a lump of coal. You should, in theory, be able to get just as much energy out of an 1100 degree coal furnace deriving 500kW of chemical energy from the coal as you can out of an 1100 degree nuclear reactor deriving 500kW of nuclear energy from the fuel.

                  Again: we know we use as much energy to bicycle some distance as we use to walk some shorter distance in a longer time. That tells us walking is inefficient, and thus that the mechanism of walking has

                  • Re: (Score:2)

                    by mark-t ( 151149 )

                    Again, it's not being suggested that walking is necessarily the overall most efficient means of unpowered transport, or necessarily anywhere even close... rather, it is being suggested that the way humans do it is about efficient in energy usage as you can physically get and still be able to actually still *call* it walking, and not just simply generalize it as "unpowered locomotion".

                    Cycling may use the same muscles as what walking does, but cycling isn't walking. You use the same muscles as walkin

                    • In theory, you can set up a set of mechanical levers and springs so that the human legs place the feet flatly on the ground one after the other in the same way that a wheel places rubber on the ground in front of rubber, albeit in wide steps instead of a continuous roll; but the legs would be attached to a rotational system, such that the energy delivery is done like a wheel.

                      Think like a bicycle with shoes tied to the wheels. Then think like a system that abstracts that away, using the wheels to power a

    • Re: (Score:2)

      by moeinvt ( 851793 )

      Uhhhh, I think the presence of the cycle is what makes cycling more efficient than walking.

    • Actually, it probably does. It sounds like a mechanical version of what kangaroos accomplished by evolving an elastic Achilles tendon - when "running" they move vertically quite a bit, but unlike muscle which can't store energy, their tendons can stretch on landing and then return virtually all of the absorbed energy on the next jump, making them the most efficient runners on the planet, almost up to what can be accomplished with wheels.

  • It would be nice to have more details. Does this device need lots of tuning for each user? It seems like it would a bit if only to adapt to size. Does it help if one is running too? Would it help marathonians get better times? What about sprinters?

    • Frankly, I see this having more use for people "needing" to hike for long distances (10-20mi) under weight.

    • Re: (Score:3)

      by plover ( 150551 )

      According to the article in Nature at http://www.nature.com/news/exo... [nature.com] , it only improves normal walking speed on level ground.

      Which is too bad. My sister in law's right side was mostly paralyzed by a stroke. She shuffles around, swinging her body weight on her good leg, and is quite the effort. I was hoping this could help her, but given her gait it's unlikely.

  • Not one poster calling this out as the April Fool's day crap article it was meant to be (posted to the firehose 2 days late I might add). Now, I'm all for the meta joke that may be happening here and whatnot, but I would have thought there would have been at least one of y'all flipping their shit over this before now, calling the Slashdot Eds lazy or stupid as hell for putting the readership through a day of nothing but an overdone joke of fake sci-fi news post after fake sci-fi news post of original cont

    • Actually, I was wrong. Longjmp did attempt to subtly inform everyone that this is an AFJ by pointing out that the original article appeared on Nature on April 1st... but it seems that the subtlety was lost on the crowd.

  • ...a system that would store the energy for a couple of hours and use that to walk me home when I'm drunk.

  • The cushioning in modern shoes steals energy from your gait. If you go barefoot or wear shoes like flip flops or business shoes with no padding and your calves develop to the point where you have your own spring.

  • The purpose of the device she's holding in her hands is unclear.

  • Am I right in hearing this?

    Scientists have now taken walking an activity many use for exercise and made it so we burn less energy by walking?

    • Re: (Score:2)

      by moeinvt ( 851793 )

      That was my first reaction as well. The only exercise most people in the USA get is walking and often it's only to and from cars or in stores.

      Could be useful for military personnel on long treks or for hiking the Appalachian trail or something. IANA physiologist, but my guess would be that this could not only reduce energy usage, but could also prevent or delay the onset of muscle cramps.

      Otherwise you're right, most people would prefer to burn more energy while walking.

    • Comment removed based on user account deletion

  • I'm going to wait for the Baron Harkonnen model to come out.

  • ... the physiological consequences of having a stride that is stronger than you are, particularly after the devices come off. Might be a good time to get that degree in podiatry.

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