Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Origami-inspired soft artificial muscles

wyss.harvard.edu

Post reply on HN
Print view View original

51–60 of 60 posts

Re: Origami-inspired soft artificial muscles

#51

Post by YeGoblynQueenne »

NickHoff wrote: post #45
YeGoblynQueenne wrote: post #34

Earlier quoted context omitted.

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 t…

In general no, single actuators move in one dimension and then only in one direction. In humans we have muscle pairs, one contracts to open the joint and the other contracts to close the joint. Of course you can do the same thing with artificial actuators, but you're right, the really interesting stuff happens when you have lots of "actuators" (like a sheet that has a hundred individually inflatable cells) or the mat…

Thanks for answering. I looked at the video again and I can see that a couple of setups use multiple muscles- that's what you're talking about I think. I'm guessing that it's going to be a lot easier to wrap a hundred individual muscles of this kind around an artificial skeleton than it is with "hard" ones.

I wonder also what all this means for more, let's say, traditional robots- like the ones we often see from Boston Dynamics. I guess it's still early to say but if I understand this correctly, people can now make cheap, light robots. Where does that leave heavy, expensive ones?

It's not a rhetorical question- Ferrari and McLaren didn't hang up their spanners just because Toyota and Datsun sell lots of cheap cars...

Re: Origami-inspired soft artificial muscles

#52

Post by [deleted] »

SketchySeaBeast wrote: post #21
mlevental wrote: post #13

Earlier quoted context omitted.

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.

So if we took away 1% of that 1000x it's own weight it would be able to lift it? It can't. It will never be able to. Only thing I got out of my engineering dynamics class - ropes don't lift. Well, that and jokes about couple moments. A lift is not a hold. A human can hold a ton of weight against gravity, but that's not them lifting it. See the squat. You can put a huge amount of weight on your back compared to the am…

[deleted]

Re: Origami-inspired soft artificial muscles

#53

Post by QAPereo »

NickHoff wrote: post #30

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 some…

If you had a swarm of 1000 small robots, each of which has minimal power and sensors, what would you do with it?

Do you need to ask? Look around, although many uses positive and negative would be found the primary two would be: espionage and “warfare” in that order.

Re: Origami-inspired soft artificial muscles

#54

Post by creep »

mark-r wrote: post #38
YeGoblynQueenne wrote: post #34

Earlier quoted context omitted.

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 t…

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?

I can imagine this being modified for spring-like muscles, with a more elastic material. Other than that, you can just suck the air out faster (which has a limit) would work better with shorter muscle "segments".

Re: Origami-inspired soft artificial muscles

#55

Post by keenerd »

tomp wrote: post #16
mlevental wrote: post #13

Earlier quoted context omitted.

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.

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.

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.

Re: Origami-inspired soft artificial muscles

#57

Post by icc97 »

xchaotic wrote: post #11

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...

I think the gripping part is the important bit. You can't get a steel wire to open and then close on an object and lift it.

Re: Origami-inspired soft artificial muscles

#59

Post by tikwidd »

NickHoff wrote: post #30

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 some…

Do you know of any way to "charge" the vacuum that drives these over a long period (from differences in air pressure?) so that they could passively build up energy and release in short bursts?

Re: Origami-inspired soft artificial muscles

#60

Post by eggy »

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!
Post reply on HN