8 ms·

Origami-inspired soft artificial muscles

200 points by lithander 9y ago

cdancette 9y ago
They are basically inflating and deflating balloons filled with some flexible structure. So 1000x might not be that impressive, because they are very lightweight. And I guess it requires a big pumping device in addition to the muscle (which weight is not included in the calculation, but certainly should be).
- blacksmith_tb 9y ago
  The weight of the compressor is important, but one compressor could be driving lots of 'muscles' via opening and closing valves, so it isn't completely disingenuous. It's analogous to, say, a robot with six motors, all powered from a single battery.
  - arghwhat 9y ago
    A compressor driving more of these hydraulic actuators need to be larger and heavier than one driving one hydraulic actuator. Rather than battery and many motors, its more like motor with many transmissions and clutches. Vacuum is also a bad choice of medium... It requires stronger pumps, stronger hoses, better seals, etc.
deleted 9y ago
[deleted]
deleted 9y ago
[deleted]
fallingfrog 9y ago
It looks like this is some kind of pneumatic system, and IMHO if you're calculating strength/weight you would need to take into account the weight of the air compressor, to have a fair comparison with biological muscle. Not to mention the fact that air compressors need to have an energy source, and are quite noisy.
- JoeAltmaier 9y ago
  So its the limit, at scale. Build a big compressor, run a bigger machine with artificial muscle, the weight of the compressor becomes a small part of the whole.
  - cdancette 9y ago
    Pneumatic to kinetic energy is much less efficient than electric to kinetic, so you're going to waste a lot of energy. And I guess the body is even better at energy efficiency
    - JoeAltmaier 9y ago
      But apparently the efficiency of these muscle fibres are greater than that of electric ones. So maybe a win?
- keenerd 9y ago
  The "big new thing" about this is that it doesn't use compressed air the way traditional air muscles do. It doesn't use compressed air at all. You're probably going to say that vacuum pumps are noisy/heavy next. But this doesn't need traditional high-grade vacuum pumps, very low grade will work. And of course it is entirely moot for industrial machines that stand in place. From what I can tell the trick comes from the pleating to massively increase surface area, giving atmospheric pressure more to work with. I've been working with robotics (as a hobbyist) my entire life. This is the most exciting thing that I've seen in a while and I'll be building prototype knockoffs all week.
  - DennisP 9y ago
    If you get something working I'd love to see a how-to article.
    - cr0sh 9y ago
      Heck, you could probably replicate it somewhat with a plastic baggie, some bits of cardboard, and a straw. Add some duct tape and hot glue, and you'd be set.
xchaotic 9y ago
The 1000x comparison is silly - in a straight up lifting of things, a simple steel wire can probably lift 100000x times it's weight. The tech has it's uses and they should highlight the flexibility rather than perceived strength...
- tomp 9y ago
  A steel wirte isn't lifting anything, it's just holding.
  - mlevental 9y ago
    i don't understand what this means. you understand that g = 9.81 m/s^2 ... every second? the difference between colloquial lifting and just holding is a matter of applying on the order of just 1% more force.
    - toasterlovin 9y ago
      There is a difference between a material’s chemical bonds resisting the acceleration of gravity and actually being able to lift an object from one height to a second, higher height.
    - tomp 9y ago
      I'm not talking about force, but about energy. To hold something suspended in air, you don't need any energy. But a steel wire can't lift anything, you need to have a motor (or muscle) that actually expends energy to move the object higher.
      - deleted 9y ago
        [deleted]
      - keenerd 9y ago
        A steel wire can lift things all by itself. Just cool the wire. If you disagree with this, consider the motor or hydraulic cylinder that can't lift anything either. (Without an external source of energy like a battery or compressor.) I'm half serious about this. The other main "artificial muscle" technology is nichrome wire after all.
sova 9y ago
This is tremendous and probably what all robots that interact with humans will look like in the next 50-100. Affordable flexible membranes able to grasp and grapple with our real world, and also gentle enough (when programmed correctly) to not harm humans and other beings, this is the future right here. Very exciting. Focus on the information and less on the headline, guys.
- gene-h 9y ago
  I am extremely doubtful of this future. A big part of the reason we are considering soft robots today is safety, that if the robot hits a human it won't hurt them. If we can make robots smart enough that they never hit humans this is no longer a problem. Another reason is making things compliant so that we can grip objects because we have yet to figure out grasping. If we solve grasping, we no longer need compliant grippers. In addition, pneumatics which this work focused on, are probably not the future. Pneumatics are not that efficient, are noisy, and are limited by the compressibility of air. The compressibility of air limits how fast these devices can actuate, their stiffness, and even how efficient pneumatic systems can get. Efficiency alone might be enough to encourage future robot makers to use something else. Stiffness is another compelling argument against both pneumatic robots and soft robots. The max rate at which a robot can do stuff and react to things is dictated by its resonant frequency and mass. Sure we can make our robot very light, but we aren't going to be able to change the mass of things we desire the robot to manipulate. So it is still desirable to have robots with higher stiffness. Really, a number of different technologies could make this obsolete within 50 years. For example, electric artificial muscles, slightly better rotary electric actuators along with rapid robotic assembly enabling stuff to have huge number of moving parts, or even advanced nanotechnology.
wellboy 9y ago
So how much is that compared to a human. A 3kg biceps can lift 30kgs of weight, so artifical muscles are 100x stronger than human's?
Panoramic 9y ago
So impressive. I could see human exoskeletons being made with this type of tech.
NickHoff 9y ago
I did my PhD with this group (Rob Wood). When I was there, these kind of actuators, and the robots you would put them in, were just getting started. It's great to see how far they've come. One of the great benefits of these soft actuators is that you can embed them in soft structures and then get smooth movement in multiple directions. Instead of a rigid robotic arm with a few degrees of freedom, you could build something like a snake or an elephant trunk. Another exciting area of research (my focus) is that since these actuators are fairly cheap, you could make lots and lots of robots with them. Think thousands. If you had a swarm of 1000 small robots, each of which has minimal power and sensors, what would you do with it? How would they coordinate their behavior? How would they communicate? For that matter, how would you even turn them all on? Swarm algorithms are fun to think about on robots, but are also useful for other problems out in the normal world. (Don't focus on the "1000x" claim. It's true depending on how you measure, but it's not the exciting part.)
- YeGoblynQueenne 9y ago
  Well, since you've worked with those kinds of actuators I hope you can clarify something I wasn't sure about in the article: can the same muscle perform different actions? For example, could you have a muscle that can bend to the left, then to the right of some central line? I'm asking because the statement [edit: in the article] that "designing how the skeleton folds defines how the whole structure moves" makes me think that perhaps the range of motions each muscle can perform is limited by construction. Ahem. That's not to downplay the obvious usefuleness of such a device. As far as I'm concerned t's the first time in ages I find a robotics piece of news cool.
  - mark-r 9y ago
    It does seem from the description that only one motion is possible for one of these muscles. Full motion would require combining multiple muscles with complementary motion, similar to the way the body works. The speed seems much slower than that of an actual muscle. Is this inherent in the technology or just a limitation of the current prototypes?
Digit-Al 9y ago
So when do I get my Doctor Octopus style robo arms? :-)
Numberwang 9y ago
"Artifical muscles can also lift, grip and twist objects." I want to see it crush as well.
clickok 9y ago
Neat!. I am working on artificial muscle as a side project[0], especially the kind you can (cheaply) 3d-print. Earlier work used these sorts of soft actuators similar to regular muscle-- you make a bunch of actuators that move in a particular direction, strap them to a skeleton, and then activate them in various combinations to move the skeleton. 3D printing, on the other hand, allows you to build more complex actuators (that don't necessarily apply force in a line). Origami-inspired designs (particularly rigid origami[1]) are related, in that you can design a particular folding pattern and have it fold and unfold to exert force in a particular way. I was originally inspired by the work on artificial muscles actuated by a phase change (liquid to gas, with attendant increase in pressure) from Columbia[2]. Some combination of the two techniques might be better than either alone, allowing for fast-twitch soft actuators to fill the roles that servos stepper motors have previously occupied. Plus, they're likely to be cheaper in general, customizable to specific tasks, and probably safer in situations where humans might get in the way of the robot's motion. ---------- 0. Most of the time I am working on reinforcement learning theory, and so building an actuator with difficult-to-model dynamics seems strange. However there's a lot RL could offer here, either learning how to control those dynamics from scratch or refining an existing model. 1. Wikipedia and its related/external links have a good overview: https://en.wikipedia.org/wiki/Rigid_origami https://en.wikipedia.org/wiki/Rigid_origami If you just want a cool example of What Rigid Origami Can Do For You, check out: https://en.wikipedia.org/wiki/Miura_fold https://en.wikipedia.org/wiki/Miura_fold 2. See the press release: http://engineering.columbia.edu/news/hod-lipson-lifelike-robots http://engineering.columbia.edu/news/hod-lipson-lifelike-rob... and the associated paper: https://www.nature.com/articles/s41467-017-00685-3 https://www.nature.com/articles/s41467-017-00685-3
bawana 9y ago
I wonder if this would make a better penile prosthesis for erectile dysfunction...
juanmirocks 9y ago
I cannot stop but recalling the last prodigy of Boston Dynamics. Paraphrasing Elon Musk's words: This is nothing. In a few years, ... https://twitter.com/elonmusk/status/934888089058549760 https://twitter.com/elonmusk/status/934888089058549760
grkvlt 9y ago
FYI, the associated paper from PNAS is http://www.pnas.org/content/early/2017/11/21/1713450114.full.pdf http://www.pnas.org/content/early/2017/11/21/1713450114.full...
bjd2385 9y ago
Reminds me of cell flagella.
eggy 9y ago
I recall when I was building animatronics in the 90s there was a pneumatic air bladder "muscle" at the time wrapped in stainless steel weave basket. So instead of using a rigid cylinder with rod, when you inflated the bladder its length contracted. You could make an arm bend and the appearance of a bulging bicep! Somewhat similar principle, but animatronics doesn't use high-volume parts, so it never took off. These origami-inspired actuators seem really cool!

200 points by lithander 9y ago

They are basically inflating and deflating balloons filled with some flexible structure. So 1000x might not be that impressive, because they are very lightweight. And I guess it requires a big pumping device in addition to the muscle (which weight is not included in the calculation, but certainly should be).

blacksmith_tb 9y ago
The weight of the compressor is important, but one compressor could be driving lots of 'muscles' via opening and closing valves, so it isn't completely disingenuous. It's analogous to, say, a robot with six motors, all powered from a single battery.
- arghwhat 9y ago
  A compressor driving more of these hydraulic actuators need to be larger and heavier than one driving one hydraulic actuator. Rather than battery and many motors, its more like motor with many transmissions and clutches. Vacuum is also a bad choice of medium... It requires stronger pumps, stronger hoses, better seals, etc.

deleted 9y ago

[deleted]

deleted 9y ago

[deleted]

fallingfrog 9y ago

It looks like this is some kind of pneumatic system, and IMHO if you're calculating strength/weight you would need to take into account the weight of the air compressor, to have a fair comparison with biological muscle. Not to mention the fact that air compressors need to have an energy source, and are quite noisy.

JoeAltmaier 9y ago
So its the limit, at scale. Build a big compressor, run a bigger machine with artificial muscle, the weight of the compressor becomes a small part of the whole.
- cdancette 9y ago
  Pneumatic to kinetic energy is much less efficient than electric to kinetic, so you're going to waste a lot of energy. And I guess the body is even better at energy efficiency
  - JoeAltmaier 9y ago
    But apparently the efficiency of these muscle fibres are greater than that of electric ones. So maybe a win?
keenerd 9y ago
The "big new thing" about this is that it doesn't use compressed air the way traditional air muscles do. It doesn't use compressed air at all. You're probably going to say that vacuum pumps are noisy/heavy next. But this doesn't need traditional high-grade vacuum pumps, very low grade will work. And of course it is entirely moot for industrial machines that stand in place. From what I can tell the trick comes from the pleating to massively increase surface area, giving atmospheric pressure more to work with. I've been working with robotics (as a hobbyist) my entire life. This is the most exciting thing that I've seen in a while and I'll be building prototype knockoffs all week.
- DennisP 9y ago
  If you get something working I'd love to see a how-to article.
  - cr0sh 9y ago
    Heck, you could probably replicate it somewhat with a plastic baggie, some bits of cardboard, and a straw. Add some duct tape and hot glue, and you'd be set.

xchaotic 9y ago

The 1000x comparison is silly - in a straight up lifting of things, a simple steel wire can probably lift 100000x times it's weight. The tech has it's uses and they should highlight the flexibility rather than perceived strength...

tomp 9y ago
A steel wirte isn't lifting anything, it's just holding.
- mlevental 9y ago
  i don't understand what this means. you understand that g = 9.81 m/s^2 ... every second? the difference between colloquial lifting and just holding is a matter of applying on the order of just 1% more force.
  - toasterlovin 9y ago
    There is a difference between a material’s chemical bonds resisting the acceleration of gravity and actually being able to lift an object from one height to a second, higher height.
  - tomp 9y ago
    I'm not talking about force, but about energy. To hold something suspended in air, you don't need any energy. But a steel wire can't lift anything, you need to have a motor (or muscle) that actually expends energy to move the object higher.
    - deleted 9y ago
      [deleted]
    - keenerd 9y ago
      A steel wire can lift things all by itself. Just cool the wire. If you disagree with this, consider the motor or hydraulic cylinder that can't lift anything either. (Without an external source of energy like a battery or compressor.) I'm half serious about this. The other main "artificial muscle" technology is nichrome wire after all.

sova 9y ago

This is tremendous and probably what all robots that interact with humans will look like in the next 50-100. Affordable flexible membranes able to grasp and grapple with our real world, and also gentle enough (when programmed correctly) to not harm humans and other beings, this is the future right here. Very exciting. Focus on the information and less on the headline, guys.

gene-h 9y ago
I am extremely doubtful of this future. A big part of the reason we are considering soft robots today is safety, that if the robot hits a human it won't hurt them. If we can make robots smart enough that they never hit humans this is no longer a problem. Another reason is making things compliant so that we can grip objects because we have yet to figure out grasping. If we solve grasping, we no longer need compliant grippers. In addition, pneumatics which this work focused on, are probably not the future. Pneumatics are not that efficient, are noisy, and are limited by the compressibility of air. The compressibility of air limits how fast these devices can actuate, their stiffness, and even how efficient pneumatic systems can get. Efficiency alone might be enough to encourage future robot makers to use something else. Stiffness is another compelling argument against both pneumatic robots and soft robots. The max rate at which a robot can do stuff and react to things is dictated by its resonant frequency and mass. Sure we can make our robot very light, but we aren't going to be able to change the mass of things we desire the robot to manipulate. So it is still desirable to have robots with higher stiffness. Really, a number of different technologies could make this obsolete within 50 years. For example, electric artificial muscles, slightly better rotary electric actuators along with rapid robotic assembly enabling stuff to have huge number of moving parts, or even advanced nanotechnology.

wellboy 9y ago

So how much is that compared to a human. A 3kg biceps can lift 30kgs of weight, so artifical muscles are 100x stronger than human's?

Panoramic 9y ago

So impressive. I could see human exoskeletons being made with this type of tech.

NickHoff 9y ago

I did my PhD with this group (Rob Wood). When I was there, these kind of actuators, and the robots you would put them in, were just getting started. It's great to see how far they've come. One of the great benefits of these soft actuators is that you can embed them in soft structures and then get smooth movement in multiple directions. Instead of a rigid robotic arm with a few degrees of freedom, you could build something like a snake or an elephant trunk. Another exciting area of research (my focus) is that since these actuators are fairly cheap, you could make lots and lots of robots with them. Think thousands. If you had a swarm of 1000 small robots, each of which has minimal power and sensors, what would you do with it? How would they coordinate their behavior? How would they communicate? For that matter, how would you even turn them all on? Swarm algorithms are fun to think about on robots, but are also useful for other problems out in the normal world. (Don't focus on the "1000x" claim. It's true depending on how you measure, but it's not the exciting part.)

YeGoblynQueenne 9y ago
Well, since you've worked with those kinds of actuators I hope you can clarify something I wasn't sure about in the article: can the same muscle perform different actions? For example, could you have a muscle that can bend to the left, then to the right of some central line? I'm asking because the statement [edit: in the article] that "designing how the skeleton folds defines how the whole structure moves" makes me think that perhaps the range of motions each muscle can perform is limited by construction. Ahem. That's not to downplay the obvious usefuleness of such a device. As far as I'm concerned t's the first time in ages I find a robotics piece of news cool.
- mark-r 9y ago
  It does seem from the description that only one motion is possible for one of these muscles. Full motion would require combining multiple muscles with complementary motion, similar to the way the body works. The speed seems much slower than that of an actual muscle. Is this inherent in the technology or just a limitation of the current prototypes?

Digit-Al 9y ago

So when do I get my Doctor Octopus style robo arms? :-)

Numberwang 9y ago

"Artifical muscles can also lift, grip and twist objects." I want to see it crush as well.

clickok 9y ago

Neat!. I am working on artificial muscle as a side project[0], especially the kind you can (cheaply) 3d-print. Earlier work used these sorts of soft actuators similar to regular muscle-- you make a bunch of actuators that move in a particular direction, strap them to a skeleton, and then activate them in various combinations to move the skeleton. 3D printing, on the other hand, allows you to build more complex actuators (that don't necessarily apply force in a line). Origami-inspired designs (particularly rigid origami[1]) are related, in that you can design a particular folding pattern and have it fold and unfold to exert force in a particular way. I was originally inspired by the work on artificial muscles actuated by a phase change (liquid to gas, with attendant increase in pressure) from Columbia[2]. Some combination of the two techniques might be better than either alone, allowing for fast-twitch soft actuators to fill the roles that servos stepper motors have previously occupied. Plus, they're likely to be cheaper in general, customizable to specific tasks, and probably safer in situations where humans might get in the way of the robot's motion. ---------- 0. Most of the time I am working on reinforcement learning theory, and so building an actuator with difficult-to-model dynamics seems strange. However there's a lot RL could offer here, either learning how to control those dynamics from scratch or refining an existing model. 1. Wikipedia and its related/external links have a good overview: https://en.wikipedia.org/wiki/Rigid_origami https://en.wikipedia.org/wiki/Rigid_origami If you just want a cool example of What Rigid Origami Can Do For You, check out: https://en.wikipedia.org/wiki/Miura_fold https://en.wikipedia.org/wiki/Miura_fold 2. See the press release: http://engineering.columbia.edu/news/hod-lipson-lifelike-robots http://engineering.columbia.edu/news/hod-lipson-lifelike-rob... and the associated paper: https://www.nature.com/articles/s41467-017-00685-3 https://www.nature.com/articles/s41467-017-00685-3

bawana 9y ago

I wonder if this would make a better penile prosthesis for erectile dysfunction...

juanmirocks 9y ago

I cannot stop but recalling the last prodigy of Boston Dynamics. Paraphrasing Elon Musk's words: This is nothing. In a few years, ... https://twitter.com/elonmusk/status/934888089058549760 https://twitter.com/elonmusk/status/934888089058549760

grkvlt 9y ago

FYI, the associated paper from PNAS is http://www.pnas.org/content/early/2017/11/21/1713450114.full.pdf http://www.pnas.org/content/early/2017/11/21/1713450114.full...

bjd2385 9y ago

Reminds me of cell flagella.

eggy 9y ago

I recall when I was building animatronics in the 90s there was a pneumatic air bladder "muscle" at the time wrapped in stainless steel weave basket. So instead of using a rigid cylinder with rod, when you inflated the bladder its length contracted. You could make an arm bend and the appearance of a bulging bicep! Somewhat similar principle, but animatronics doesn't use high-volume parts, so it never took off. These origami-inspired actuators seem really cool!