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Fishing Line As Artificial "Muscle"

samzenpus posted about 5 months ago | from the reeling-in-the-big-one dept.

Science 111

brindafella writes "Researchers have made what they describe as an 'almost embarrassing' discovery, that twisted nylon fishing line can form a 'powerful, large-stroke, high-stress artificial muscle' capable of lifting as much as 100 times more weight than human muscles. They twisted the fishing line, then heated it to 'set' the shape-memory. The scientists are from the Australian Research Centre of Excellence for Electromaterials Science at the University of Wollongong, and the University of Texas. The findings are published in Science magazine."

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Heck (1)

Anonymous Coward | about 5 months ago | (#46303147)

I could have told them that, but I was too busy fishing.

Re:Heck (2)

Cryacin (657549) | about 5 months ago | (#46303259)

More like tying flies. 95% of time tying em. 5% of the time losing em.

so they invented the spring (1, Troll)

Gothmolly (148874) | about 5 months ago | (#46303167)

They took a material with high tensile strength, coiled it, and annealed it into shape - and now it resists tension! Call Isaac Newton!

Re:so they invented the spring (4, Informative)

tippe (1136385) | about 5 months ago | (#46303235)

FTFA:

Spinks says to use these springs as artificial muscles heat is again applied, causing the whole coil to contract.
Critically, with the ordinary fibres, the amount of contraction is as much as 50 per cent of the starting length of the coil, he says.

That's a little more "muscle"-like than your average spring, I'd say.

Re: so they invented the spring (1)

O('_')O_Bush (1162487) | about 5 months ago | (#46303265)

Or... tendon.

Re:so they invented the spring (1)

colin_faber (1083673) | about 5 months ago | (#46304671)

Then the average spring yes, but a nitinol spring will do just that, with much more retraction force when heated.

Re:so they invented the spring (5, Informative)

noahwh (1545231) | about 5 months ago | (#46304719)

They're not claiming to have invented a unique mechanism. They're claiming to have implemented a useful known mechanism in a low cost material.

Re:so they invented the spring (0)

Anonymous Coward | about 5 months ago | (#46303239)

Talk about reinventing the wheel.

Re:so they invented the spring (1)

Dunbal (464142) | about 5 months ago | (#46303547)

Not reinventing - modifying. Like sticking a pneumatic rubber tube on that wooden wagon wheel and noticing its better.

Re:so they invented the spring (2, Interesting)

Anonymous Coward | about 5 months ago | (#46303267)

The interesting part is that it contracts when heat is applied - like a shape memory alloy, but at a fraction of the cost.

Re:so they invented the spring (0)

Anonymous Coward | about 5 months ago | (#46304165)

Problems arise when you remember that muscle has enough to pull the tendon off the bone.

It's "The Science Of The Bionic Man" all over again. Lifting a heavy weight with your bionic arm shearing that arm off at the non-bionic shoulder...

Re:so they invented the spring (1)

Sockatume (732728) | about 5 months ago | (#46303315)

They're actually shape memory materials.

Re:so they invented the spring (2)

rmdingler (1955220) | about 5 months ago | (#46303321)

Many breakthroughs are imaginative extensions of existing technologies.

Imagination is more important than knowledge

A.E.

Re:so they invented the spring (2)

oneandoneis2 (777721) | about 5 months ago | (#46303345)

Almost: They invented a *self-coiling* spring - one that can get longer or shorter to order.

You know, like muscles do...

Re:so they invented the spring (0)

Anonymous Coward | about 5 months ago | (#46303639)

Didnt RTFA then?

Heat is the limiting factor in our muscles, too (3, Interesting)

drinkypoo (153816) | about 5 months ago | (#46303169)

If you can prevent a person from overheating, you can keep them working 2-4 times longer. Muscles are bathed in blood, what coolant will be used for nylon? I suppose automotive stuff would be acceptable.

Re:Heat is the limiting factor in our muscles, too (0)

Sockatume (732728) | about 5 months ago | (#46303369)

Heat isn't the limiting factor here, it's what causes the fibre to actuate.

Re:Heat is the limiting factor in our muscles, too (4, Insightful)

drinkypoo (153816) | about 5 months ago | (#46303477)

Heat isn't the limiting factor here, it's what causes the fibre to actuate.

Yes, but they will have to be cooled in order to de-actuate. The rate of thermal transfer is going to limit the working rate. It's fascinating stuff.

Re:Heat is the limiting factor in our muscles, too (1)

ciderbrew (1860166) | about 5 months ago | (#46303573)

at this scale getting heat and coolant around the wire will be easy.

Re:Heat is the limiting factor in our muscles, too (1)

drinkypoo (153816) | about 5 months ago | (#46303693)

Sure, for a single strand. But actuators will be built up of multiple twisted strands, just like actual muscles.

Re:Heat is the limiting factor in our muscles, too (1)

tmosley (996283) | about 5 months ago | (#46303867)

He's saying that since the "muscle" is so much stronger, you need much less of it, so there is plenty of room for coolant. You only need 1% of the "muscle" mass as you would for regular muscle.

Re:Heat is the limiting factor in our muscles, too (1)

drinkypoo (153816) | about 5 months ago | (#46303949)

He's saying that since the "muscle" is so much stronger, you need much less of it, so there is plenty of room for coolant. You only need 1% of the "muscle" mass as you would for regular muscle.

Nylon isn't as dense as muscle, and we'll want to do more work than a human muscle can do in many conditions.

Re:Heat is the limiting factor in our muscles, too (1)

poetmatt (793785) | about 5 months ago | (#46304261)

Which - based on the implications, would require 1/100th of the muscle just to seek parity with a normal human muscle. So, it sounds like this should be quite easy to have it do much more work than a human muscle.

Re:Heat is the limiting factor in our muscles, too (1)

HornWumpus (783565) | about 5 months ago | (#46304449)

This is going to compete with hydraulic cylinders and pumps or winches and cables, not human muscles. Generating 220C for even moderate sized masses inside a living body is problematic to say the least.

Imagine an artificial heart made of this goo. It might pump blood well. But it would denature the protein in the blood while pumping.

Re:Heat is the limiting factor in our muscles, too (1)

ultranova (717540) | about 5 months ago | (#46305213)

This is going to compete with hydraulic cylinders and pumps or winches and cables, not human muscles.

No, it won't. One of the nice things about hydraulics is that when you get the load where you want it, just shut the valve and it stays right there. And cables are easy to secure with a simple brake. This thing, on the other hand, requires you to keep pumping heat - and actively regulate it - to stay at the desired length.

There might be use for this thing, for example in a mechanically simple heat engine, but it doesn't even remotely compete with hydraulics.

Re:Heat is the limiting factor in our muscles, too (1)

GodInHell (258915) | about 5 months ago | (#46305397)

There might be use for this thing, for example in a mechanically simple heat engine, but it doesn't even remotely compete with hydraulics.

In those applications where hydraulics / winches and cables work - sure - but what about where they're a poor substitute for something that acts like natural muscle - like say - robotics?

Collaborator Professor Geoff Spinks says it is a much-sought breakthrough that could open the door to the use of artificial muscles in clothing and prosthetic manufacture, robotics, and as a green energy source.

- from TFA.

Notably - the article claims that the reaction is nearly as fast as human muscle - which could be interesting. Also, most of the practical applications listed in the article take advantage of the fact that the fiber responds to heat - which can include ambient temperatures, to automate the opening and closing of vents and other heat control systems without spending energy on control systems or motors.

Re:Heat is the limiting factor in our muscles, too (1)

Whorhay (1319089) | about 5 months ago | (#46306265)

I think the key is that this has to potential to be much lighter weight and possibly less bulky than hydraulic systems. Prosthetic limbs and exo skeletons being a prime possibility for this kind of stuff. The only issue I can see is that they are talking about temperatures that would be dangerous for people. I believe those temperatures though are the point at which the material contracts to 50% of it's normal length. I suspect working with lower temperatures would work so long as you don't need that 50% change in length, maybe working with 25% instead.

Re:Heat is the limiting factor in our muscles, too (1)

ciderbrew (1860166) | about 5 months ago | (#46304475)

Engines have been dealing with cooling and heating for years. Wear and tear on moving parts expanding and contracting should be ok.
Values, joints and seals will break at the wrong time and leak over something they shouldn't.
I found this - http://www.youtube.com/watch?v... [youtube.com] Role it up, stick it in concertina piping and run hot and cold air / water / oil / tea / beer/ over it.

Re:Heat is the limiting factor in our muscles, too (1)

Sockatume (732728) | about 5 months ago | (#46304005)

Oh, I see. I assumed the original was asking how they'd ditch waste heat. So the real question is, how do you efficiently cycle it.

Re:Heat is the limiting factor in our muscles, too (1)

Jesus_666 (702802) | about 5 months ago | (#46304193)

Easy. You add some double heat sinks. If those take up too much space try to make the reactor stronger so you can put some in there.

Sure, it gets a tad more complicated if you want to build a brawler with triple-strength muscles or a high-output laser boat but if you keep track of your loadout's heat generation and maybe err on the side of cooling your 'mech should work beautifully even during heated engagements. (Pun intended.)

Well, until you run into someone packing flamethrowers, of course. Or plasma rifles.


I can't be the only one who read TFS and immediately thought "myomer".

Re:Heat is the limiting factor in our muscles, too (1)

Dunbal (464142) | about 5 months ago | (#46303557)

[citation needed] I'm calling BS on this one. Heat is certainly not the limiting factor in human muscle contraction.

Re:Heat is the limiting factor in our muscles, too (1)

Anonymous Coward | about 5 months ago | (#46303941)

He never said it was the limiting factor in contraction (power). He said it was a limiting factor in the duration of heavy work.

Re:Heat is the limiting factor in our muscles, too (0)

Dunbal (464142) | about 5 months ago | (#46305707)

Which is false.

Mechanism (3, Insightful)

symes (835608) | about 5 months ago | (#46303175)

If I read this right - they coil the line, stretch it and then use heat to return it back to the original coiled state. This then provides lift. I am wondering how much heat is required though. If you have enough of these filaments in an artificial muscle arrangement could you, while lifting your car or running for the bus, spontaneously ignite? That to one side, though, I really love these unexpected breakthroughs.

Re:Mechanism (3, Informative)

Anonymous Coward | about 5 months ago | (#46303433)

There are broadly speaking 2 varients mentioned in the paper, Nylon and Polythene. The Nylon was heated between 20C and 240C for full contraction, and the Polythene between 20C and 130C.

Re:Mechanism (0)

Anonymous Coward | about 5 months ago | (#46303449)

That should be Polyethlyene, not Polythene.

only in merkinland (1)

rewindustry (3401253) | about 5 months ago | (#46306323)

polythene is a perfectly legitimate synonym. can you say aluminium? go on - give us all a laugh..

Re:Mechanism (1)

scorp1us (235526) | about 5 months ago | (#46303509)

and varients should be variants. ;-)

Re:Mechanism (2)

HornWumpus (783565) | about 5 months ago | (#46304281)

It should be noted that the crystal melt temperature of nylon 6-6 is 250-260 C.

I thought fishing line was nylon 6. Whose crystalline melt temp is 215-220 C.

Both glass transitions are in the 50-75 C range.

In any case 240C routine heating isn't going to be a long lived 'muscle'.

Re:Mechanism (0)

Anonymous Coward | about 5 months ago | (#46303943)

I was thinking about this yesterday when I heard about this story. There are some materials that have piezo electric properties, one of which is pvdf monofiliment fishing line. I would expect that this material would be able to perform similarly without the need to use heat as the energy source.

Fly fishermen have used this property for years (5, Informative)

BitZtream (692029) | about 5 months ago | (#46303199)

I've been using this property to tie flies since I was 5-7 years old ... 30 years ago. It wasn't new then. Admittedly, I never thought about using it or controlling it, but heat treating monofiliment isn't exactly new. Want a tight fly? Heat treat it, then give it a pinch to hold its shape after its good and warm. Use your fingers, not a tool that will nick the line and make it weak, as the heat treating already weakened its tensile strength considerably.

Mono hasn't been around that long so I suppose fly fishermen hasn't been doing it that long either, but still, this property is well known.

If only we had better search tools to be able to find things like this without rediscovering it. Its not wasted research by any means, but it sure does seem like we could make much more progress if we could benefit from the sum of human knowledge rather than the little bit we have domain specific knowledge of and trying to shoehorn everything else into it.

Re:Fly fishermen have used this property for years (4, Informative)

Sockatume (732728) | about 5 months ago | (#46303295)

Suffice to say the process they used is a bit more nuanced than that; I can't link to the paper's figures because of the paywall, but they developed complex hierarchical microstructures of the filaments, and different ones for different applications. (E.g. one structure gives you a fabric with pores that open as it warms up.)

Re:Fly fishermen have used this property for years (2)

The Grim Reefer (1162755) | about 5 months ago | (#46303333)

Monofilament fishing line [wikipedia.org] has been around since 1939 and the most popular type that is used today has been on the market since 1959. Considering all of the uses it has been repurposed for in the last half a century, I wouldn't consider it new, except in a geological timeframe.

Things like this discovery always make me laugh. People will make comments about how obvious this was. But it wasn't until the first time someone figured it out. Otherwise it should have happened sometime in the last fifty years.

Re: Fly fishermen have used this property for year (2)

iamhassi (659463) | about 5 months ago | (#46303755)

I'm sure someone figured it out long ago and I'm sure fishing line has probably already been used for this purpose. This is just the first time someone was willing to swallow their pride and publish it in a scientific journal. I'm sure there are scientists and engineers out there saying "no duh" and "thanks captian obvious" to this article.

Re: Fly fishermen have used this property for year (1)

The Grim Reefer (1162755) | about 5 months ago | (#46304397)

I'm sure someone figured it out long ago and I'm sure fishing line has probably already been used for this purpose.

Why are you so sure?

This is just the first time someone was willing to swallow their pride and publish it in a scientific journal.

What pride? It's a legitimate discovery. With all of the dumb shit that gets patented these days, I'm sure someone would have rushed to the USPTO with it

I'm sure there are scientists and engineers out there saying "no duh" and "thanks captian obvious" to this article.

Why? With all of the research going into this field, you really think that something that works well and is cheap would be completely ignored? I think it's more likely that people had the knowledge that mono-filament line had these properties. But never thought that it would have the capacity to contract and relax with the amount of force that it does. So they never bothered to test it until now.

Re: Fly fishermen have used this property for year (1)

HornWumpus (783565) | about 5 months ago | (#46304473)

You assume this works well and lasts? Note the temperature delta between the operating temp and melting.

Re: Fly fishermen have used this property for year (1)

The Grim Reefer (1162755) | about 5 months ago | (#46305191)

I don't know what the temperature delta is, as I didn't see it listed anywhere. Still, this is being done with an off the shelf product. I would imagine a purpose designed version would be able to eliminate the issue, if it is one.

However from Science Daily, The muscle strokes also are reversible for millions of cycles as the muscles contract and expand under heavy mechanical loads." [sciencedaily.com] . I wish they would have better explained what they mean by millions though. There's a pretty big difference between 2 million and 800 million. But again, 2 million for an off the shelf product that costs less than $10 is pretty cool if you ask me.

Re:Fly fishermen have used this property for years (0)

Anonymous Coward | about 5 months ago | (#46303347)

Mono hasn't been around that long

Mono has been around since I started fishing in the early 70s...

Re:Fly fishermen have used this property for years (1)

shadowrat (1069614) | about 5 months ago | (#46303385)

I don't think they rediscovered it. More likely someone is aware of it from fly fishing and they just decided to rigorously test it, and then take credit for discovering it. It's just good science.

Re:Fly fishermen have used this property for years (1)

Intrepid imaginaut (1970940) | about 5 months ago | (#46303425)

I suspect this will become an increasing problem as the need for in-depth specialisation increases with the advance of the sciences.

Re:Fly fishermen have used this property for years (0)

Anonymous Coward | about 5 months ago | (#46303441)

This. All of this. Yes.

Re:Fly fishermen have used this property for years (2)

arielCo (995647) | about 5 months ago | (#46303453)

Do you mean that the treated nylon re-twisted spontaneously upon heating? I already know that to make a tight knot on a stiff material you can soften it with heat, but this is about "shape memory" - twist, heat, relax; then it will coil up actively when heated:

Spinks says they attached the fishing line to an electric drill and applied tension to the thread.

As it twists, the fibre forms tight coils in a spring-like arrangement. Once heat is applied to the coils it permanently fixes that spring-like shape.

Spinks says to use these springs as artificial muscles heat is again applied, causing the whole coil to contract.

Re:Fly fishermen have used this property for years (0)

Anonymous Coward | about 5 months ago | (#46303591)

yes you do this to give memory to home-made braided monofilament leaders used in fly fishing. The difference is you are heat treating the leader to make it uncoil straight and deliver the fly nicely. Google it , there are instructions on the web..

Re:Fly fishermen have used this property for years (0)

Anonymous Coward | about 5 months ago | (#46303669)

You're missing the point, the new discovery is that it then changes shape when you apply heat a second time, not the first annealing process.

Re:Fly fishermen have used this property for years (1)

LifesABeach (234436) | about 5 months ago | (#46303775)

So you would place humanities needs before the needs of Intellectual Property Lawyers?

Re:Fly fishermen have used this property for years (2)

ceoyoyo (59147) | about 5 months ago | (#46304015)

Heating plastic to make it shrink or hold a new shape isn't new. Getting it to cycle from shrunken to unshrunken and back is.

Re:Fly fishermen have used this property for years (1)

bugs2squash (1132591) | about 5 months ago | (#46304351)

I don't think it cycles back. I didn't see that in the article. Just that in the lab you stretch it under heat. wait to cool, then when reheated it can shrink again, one time (or perhaps more if you take it back to the lab and repeat the stretch/heat). I got the impression that once it cools after it has contracted it is then set at the contracted length.

Re:Fly fishermen have used this property for years (2)

ceoyoyo (59147) | about 5 months ago | (#46304903)

The article describes heating the filament to set it, stretching it back out, then heating it again to contract. Fly fisherman (and kids with hairdryers) only do the first part. In the paper they describe:

A coiled nylon 6,6 muscle delivered over 1 million cycles during periodic actuation at 1 Hz (Fig. 3B), raising and lowering a 10-g weight producing 22 MPa of nominal stress. This actuation was powered by applying a 30 V/cm square-wave potential (normalized to coil length) at a 20% duty cycle. Although the coiled fiber did experience creep (inset of Fig. 3B), this creep was below 2% over the 1.2 million investigated cycles, stroke amplitude was negligibly affected, and the creep rate decreased with cycling.

It does indeed cycle. Reasonably quickly and a lot of times. The article also describes some applications they've successfully built, including automatic window openers that would require multiple cycles.

Re:Fly fishermen have used this property for years (2)

jellomizer (103300) | about 5 months ago | (#46304127)

But they haven't measured and documented it. So it wasn't science, it was hearsay.
There are a lot of truths out there that science hasn't gotten to yet. Heck only a few years ago they calculated how scotch tape rips.

Re:Fly fishermen have used this property for years (0)

Anonymous Coward | about 5 months ago | (#46304703)

So did you use it to create artificial muscles 30 years ago then?

Yeah.... didn't think so.

Are you talking about just softening it with heat? (1)

raymorris (2726007) | about 5 months ago | (#46305651)

How did you reheat the fly to 220C while casting? And why?

You're not referring to just softening the plastic to shape it, are you? That's not what the article is talking about. The article is talking about setting it up so that it moves back and forth based on temperature. You heat it up, it shortens. When you stop applying heat it lengthens.

And don't forget ... (0)

Anonymous Coward | about 5 months ago | (#46303269)

... what an amazingly therapeutic and relaxing activity this is for a man. Yeah, I said it. Man. Unapologetically. You want time to let you mind wander? Let your self get in tune with the natural world? Know what it is to have to kill what you catch and eat? It's a wonderful discipline for a modern man. If you want a weekend away from the computer that's in tune with what an intelligent human being needs to live? Try fishing. An art anyone can master.

Re:And don't forget ... (1, Insightful)

Grishnakh (216268) | about 5 months ago | (#46303831)

Even better, you can do something that's just as relaxing but doesn't require a nearby lake or having to deal with smelly fish, such as watching paint dry. So exciting! Or you could just lock yourself in a featureless room and stare at the wall for a full day.

Re:And don't forget ... (1)

HornWumpus (783565) | about 5 months ago | (#46304345)

Even if you don't catch a fish, you catch a buzz.

being forced to view BETA (-1)

Anonymous Coward | about 5 months ago | (#46303275)

F*** BETA!
It makes the site look like the geneaology websites, and is NOT condusive to reading quickly.
Either force Beta to become the standard and lose the audience/participants that make the site worth reading,
or put the "Classic Slashdot" option at the top of the page and keep the setting in a cookie...

Oh, I almost forgot - Fu** BETA and get off my lawn!!!

Re:being forced to view BETA (0)

Anonymous Coward | about 5 months ago | (#46304157)

You're looking for Soylent News [soylentnews.org] Might as well get your UID now.

It's only a matter of time... (1)

hyades1 (1149581) | about 5 months ago | (#46303281)

"So tell us again, Lefty, how you got that friction burn on your pecker."

australian article and slashdot summary are wrong (0)

Anonymous Coward | about 5 months ago | (#46303283)

Not University of Texas, which is typically meant as University of Texas at Austin, but the correct school is the University of Texas at Dallas.

Re:australian article and slashdot summary are wro (1)

Attila Dimedici (1036002) | about 5 months ago | (#46303413)

Just because most people in Texas mean University of Texas at Austin when they say University of Texas does not mean that the summary is wrong. Both the University of Texas at Austin and the University of Texas at Dallas are part of the University of Texas. Just because you assume that University of Texas refers to a one subset of that institution does not mean that someone was wrong to use it to refer to another subset.

Re:australian article and slashdot summary are wro (1)

txsable (169665) | about 5 months ago | (#46303733)

Actually, when people inside and outside of Texas say "the University of Texas", they are referring to that school in Austin. The summary is definitely incorrect; University of Texas at Dallas is a different institution and while both are members of the UT System, Dallas is not a branch campus of Austin but a separate university in its own right. It would be like saying "University of California" and meaning the school in San Diego and not UC-Berkley. Or, an example for Texans, saying "Texas A&M" and meaning Prairie View A&M, which is also part of the TAMU System but not simply a branch of the main campus in College Station.

Re:australian article and slashdot summary are wro (1)

HornWumpus (783565) | about 5 months ago | (#46304693)

Berkeley was the first UC campus. But it's usually referred to as 'Cal' or 'Berserkely'. Not just an unqualified 'University of California'

Re:australian article and slashdot summary are wro (1)

Attila Dimedici (1036002) | about 5 months ago | (#46304887)

Actually, it would be like saying someone works for Pennsylvania State University when they work at Pennsylvania State University Great Valley...Oh wait, people do say that, even though most of the time people think the State College campus when they hear that. If they had been referring to the LOCATION rather than the EMPLOYER of the scientists, you might have a point. The scientists do indeed work for the University of Texas. BTW, I am pretty sure that the people who run the University of Texas encourage this particular usage.

"University of Wollongong" (1)

bradgoodman (964302) | about 5 months ago | (#46303371)

"...we're not just JUST about FTP servers anymore!"

Re:"University of Wollongong" (2)

flyingfsck (986395) | about 5 months ago | (#46303859)

You mean University of Verylongdong?

But will they regenerate? (1)

tokizr (1984172) | about 5 months ago | (#46303537)

Strain and exposure tends to destroy nylon from my experience, when a muscle fiber is broken it gets replaced by one or more new fibers, how would you efficiently replace broken coils on a artificial limb?

Re:But will they regenerate? (1)

Whorhay (1319089) | about 5 months ago | (#46303935)

Just order a new artificial muscle replacement pack on line. The huge break through here is that the materials area already commonly available and ridiculously cheap in the form needed. $5 for 1Kg of fishing line. Most of the stuff people have been testing for this kind of application are only really workable on tiny scales and use exotic and hence expensive materials.

Stretching the definition of artificial muscle (2)

MobyDisk (75490) | about 5 months ago | (#46303551)

Most artificial muscles work by applying electric current along the muscle. When the current is removed they snap back to their original shape. Using heat sounds very limiting. Presumably you cool it to get it back to the original shape, but the ABC article is light on details.

Re:Stretching the definition of artificial muscle (1)

Grishnakh (216268) | about 5 months ago | (#46303845)

Using heat sounds like it won't work very well in different environments. What happens when you try to use your artificial limb in subzero temperatures?

Re:Stretching the definition of artificial muscle (1)

Anonymous Coward | about 5 months ago | (#46304129)

Using heat sounds like it won't work very well in different environments. What happens when you try to use your artificial limb in subzero temperatures?

You've probably got that backwards. It's easier to heat an object than to dissipate heat. A cold environment would make cooling more efficient, but a hot environment would reduce that efficiency. In extreme cases where the ambient temp is at or above the max operating temp of the fiber you'd never be able to get it to change back to neutral shape.

Re:Stretching the definition of artificial muscle (1)

Grishnakh (216268) | about 5 months ago | (#46304225)

Yes, but being able to heat that object properly in a very cold environment depends on having very good insulation so that the heat isn't dissipated to the environment too quickly. Then moving the artificial limb to a hotter environment, with all that insulation still present, means you need to have an active cooling system for it to continue working, meaning the whole thing is now pretty complicated. Finally, generating heat in a precisely-controllable manner (given these challenges of insulation and cooling in different environments) isn't that easy; remember, you want to be able to finely control your "muscles" so that you can very precisely control your limbs' movements. It'd be a lot easier to use something that can be electrically actuated, and where you only need to make sure the actuator's temperature is kept within a certain range for it to work properly.

Re:Stretching the definition of artificial muscle (0)

Anonymous Coward | about 5 months ago | (#46304133)

What happens when you try to use your artificial limb in subzero temperatures?

That is the easier extreme to deal with: just apply more heat. The other extreme, removing heat in high temperatures to allow it to relax would be more difficult.

Re:Stretching the definition of artificial muscle (1)

HornWumpus (783565) | about 5 months ago | (#46304367)

The problem here is the working temperature is very near the melting temperature. You have to apply heat evenly to make it work.

Re:Stretching the definition of artificial muscle (1)

Whorhay (1319089) | about 5 months ago | (#46306389)

I believe the temperatures listed are simply the temps required in order to get the maximum contraction from the material. It is quite possible that lower temperatures would still result in enough change for some useful purpose. for example they have figured out some uses for clothing where when the wearer gets hot vents are pulled open by these special threads.

In fact many greenhouses already have vents operated through the same principle. Normally it's some metal though that as it heats it causes a venting panel to open. Depending on how hot it is the vent will open more or less. And this is also how old thermostats used to work. You had a bimetal spring that changed shape depending on temperature which actuated an electrical switch to turn the heat or AC on and off.

Re:Stretching the definition of artificial muscle (1)

ceoyoyo (59147) | about 5 months ago | (#46304041)

Actually, a lot of artificial muscles use heat. The heat is often provided by running an electric current. You could do the same with these. Electric heating wires for contraction, liquid cooling capillaries for relaxation.

Heated by electricity? (1)

DarwinSurvivor (1752106) | about 5 months ago | (#46306609)

I thought most of the electric muscles worked by having the electricity heat part of the alloy? Sounds like the same mechanism, they just need to find an easy way to do the heating outside of a lab (muscles sealed in a tube of fluid may work).

There is no energy input (1)

Karmashock (2415832) | about 5 months ago | (#46303643)

And therefore cannot be any sustained energy output. Oh sure, there's doubtless energy in the taught cables... but not enough to call it a muscle.

What they have here is a plastic spring. It can hold large weights? Amazing... Fishing line does that especially if you use a lot of it.

Am I missing something here? It seems like its just a spring to me. A spring is not a muscle.

Re: There is no energy input (1)

FishTankX (1539069) | about 5 months ago | (#46303809)

Heat is the input energy. It takes heat to actuate the muscle. After it cools it stops resisting the tension. My guess is that heat is applied through nichrome wire. Although being able to actuate at 130c makes me think you could use polyethylene coils to make a waste heat recovery engine via a reciprocating pull on a flywheel

Re: There is no energy input (1)

Karmashock (2415832) | about 5 months ago | (#46303843)

ah, that makes more sense. So you heat the wire and it relaxes... cool it and tightens up?

Re: There is no energy input (0)

Anonymous Coward | about 5 months ago | (#46303951)

The opposite - it contracts when heated and relaxes as it cools.

Re: There is no energy input (1)

Will.Woodhull (1038600) | about 5 months ago | (#46304205)

That's if the strand is coiled in the same direction as it was twisted (anterograde coil, AC). From TFA, if it is coiled opposite to its twist (retrograde coil, RC), it lengthens with the application of heat and shrinks as it cools (doing as much work on cooling as AC does on heating).

TFA mentions that other triggers than heat can be used but doesn't say anything more about it. Want more info on that.

Re: There is no energy input (1)

Whorhay (1319089) | about 5 months ago | (#46303975)

I might have gotten it wrong, but my reading of the article was that heating is actually what causes the spring to retract back into it's coiled shape, when it cools it relaxes.

Re:There is no energy input (0)

Anonymous Coward | about 5 months ago | (#46303891)

Am I missing something here? It seems like its just a spring to me. A spring is not a muscle.

Yes, you are definitely missing something.

Science fiction to reality (1)

ugen (93902) | about 5 months ago | (#46303861)

Funny, if you happen to be Russian and of that generation - this is pretty much how "bioplastic" drive was described in a sort-of-science-fiction book about "Neznaika in a sunny town" :) Here is the relevant page:
http://vseskazki.su/avtorskie-skazki/n-nosov-rasskazi/neznajka-v-solnechnom-gorode.html?start=28

I've been waiting for this one for a while.

So, anyone immediately think Mechwarrior? (0)

Anonymous Coward | about 5 months ago | (#46304239)

I'll take a 100ton Battlemaster powered by myomer fishing line, thanks!

Out today (2)

PPH (736903) | about 5 months ago | (#46304335)

Gone fishin'^H^H^H^H^H^HThermo-mechanical materials property researchin'

Fishing Line Sales Spike Dramatically (1)

Spinlock_1977 (777598) | about 5 months ago | (#46304605)

News Alert: Fishing supply stores across the world are being mobbed by crowds of fidgety nerds buying up all the fishing line their moms' will let them buy.

Cheap Robots Soon? (1)

TomRC (231027) | about 5 months ago | (#46304675)

One of my personal long standing predictions has been that when we finally get really cheap "good enough" robot muscles, personal robots will take off much like PCs did, even if the muscles have significant problems to be worked around.

I presume that with use these muscles will stretch and lose strength. But that's OK - just pair them with control software that adapts automatically. If the muscles get too weak, replace them. The main question will be how fast they degrade. If they could last in an intermittently active robot for a month, that's probably enough to get started.

Another question is how fast they can cycle without over heating and ruining them. Given the sorts of applications they describe, I suspect there are issues with speed. But one good thing about this development is that anyone can experiment with it in their garage, and many will, and solutions for fast cycling muscles will be found.

Re:Cheap Robots Soon? (1)

werepants (1912634) | about 5 months ago | (#46305567)

It seems to me that the bigger barrier is computer vision and AI issues, and I would say that as some of these things are getting closer to solved robots are very close to the "take off" point... it's arguable that it is already happening. Servos and electric motors are pretty damn good (and cheap!) and easy to control - artificial muscles have a lot of improving to do to match that. That said, the kind of uber-flexible humanoid robot that most people envision might be easier to realize if artificial muscle technology advanced.

Oh god, no (0)

Anonymous Coward | about 5 months ago | (#46305229)

After the trend with embarrassingly parallel algorithms now come embarrassing discoveries. What next, embarrassing low IQ?

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