Sup /sci/
/m/ here. Why are bipedal robots so hard to build IRL?
They aren't that hard to build. They just move slowly, since they have so much mass.
Also if it falls over, how would it get back up? You would need a crane, or three.
>>6637720
Power storage or creating power.
Balance. We use a good portion of our brains staying upright. When it comes to giant robots, you get into problems of no material being strong enough to support it,.
Energy storage. You end up needing a shit load of power to get huge things to move, even more if you want them in the shape of large bipedal robots.
>>6637756
well, it would take more power because it requires more force to move the weight in 2 steps rather than 4, and it'd need to balance itself along the way which would potentially require more power as well (assuming you would want it to be speedy)
Largely, problems of scale.
You double a human being in height, and you quadruple the surface area of their feet, but you octuple their mass.
So now, you have 8x the weight, being supported by only 4x the area.
And it only gets worse as you scale up.
3x the height = 9x the area = 27x the mass.
>>6637794
>Largely, problems of scale.
>You double a human being in height, and you quadruple the surface area of their feet, but you octuple their mass.
>So now, you have 8x the weight, being supported by only 4x the area.
>And it only gets worse as you scale up.
>3x the height = 9x the area = 27x the mass.
Humans are 2 meters, a Zaku II mobile suit is 17.5 meters.
We'll assume the human weights 80 kg
We'll also assume his foot surface area is 100cm^2, or 1m^2
>source: http://en.wikipedia.org/wiki/Pedobarography
Now lets derive the equation
h=height of human
X=given multiple of h
Y=(X^2)(foot surface area in meters)
Z=(X^3)(mass in kg)
If h=2 and the Zaku is 17.5, then X=17.5/2=8.75
Therefor
Y=(8.75^2)(1m^2)=76.5625m^2
Z=(8.75^3)(80kg)=53593.75kg=53.59375t
Now let's adjust the mass and foot area to data from the Gundam wiki
>standard mass=58.1t
There's no data on foot surface area, but it appears to be about 3x the width and 1.25 times the length (see pic) of a human foot
So the foot surface are would be roughly
(76.5625m^2)(3)(1.25)=287.109275m^2
Now 58.1t/287.109275m^2=.2023619048 metric tons per square meter
or 202.36 kilos per square meter
that doesn't sound too terrible
sorry op, you're not going to be able to rationalize your fantasies of giant robots
>>6637892
as for material, mobile suits are commonly made with titanium alloys, usually created in micro-gravity environments to insure the alloys contents are distributed easily
>>6637900
>easily
**evenly
>>6637900
> created in micro-gravity environments to insure the alloys contents are distributed evenly
lol
>>6637924
don't you know gundanium can only be made in space?
>>6637932
Gundanium is a titanium alloy?
I didn't know that.
The more I think about it you're right.
I was thinking you were talking about some kind of distribution of the types of atoms and diffusion would take care of that.
If I understand what I'm reading right now, you can grow nicer crystals in space so less discontinuities.
>>6637937
That's not me, all I know is that they said in Wing that you gots ta make it in space
>>6637720
they are hard to control because walking on flat terrain requires going through kinematic singularities. Singularities are not fun to work with.
>>6637736
>>power
because we don't have very efficient high torque actuators and we haven't optimized the walking gait/design.
Bipeds with an optimized walking gait and design are fairly efficient(compared to other walking robots), the planar biped in pic related was able to go 14 miles without recharging.
And we can do better if we implement energy recovery when walking(having the legs spring back)
>>6637951
Oh wait, you mean gundams, this study:
http://pinktentacle.com/2008/01/725000000-gundam/
found that "... Gundam will forever remain just a dream"
>15 tanks shooting a gundam.gif
>>6637892
The problem really is power scaling if you want anything with agility comparable to a human. I used this as a reference
http://www.mahq.net/mecha/gundam/msgundam/rx-78-2.htm
I just estimated the forearm length to be about 3 meters long and 1.3 meters wide. Assuming this volume is filled with 25% titanium the forearm alone would weight 4000kg.
Say you want to use this forearm to execute a punch in the same time a human would, starting with the fist at the shoulder and fully extending the arm, the center of mass of the forearm has to experience 20g.
To accelerate a mass like this in 250ms it would require 40 megawatts.
Even if I'm overestimating by a factor of 10 that kind of power is ridiculous. 4MW in an untethered vehicle just for punching. If we start trying to calculate the power to run and jump I think we'll start coming up with some wild numbers.
If you want large robots to have any kind of agility as displayed in anime you are fighting two things that compound against each other. For them to move like humans the acceleration requirements go up because you are increasing all the distances the body parts have to move through while keeping the time required constant. So we have increasing acceleration demands and the mass going up by the cube of these distances. Looking at F=ma, you have both variables on the right hand side getting very large. The result is huge force requirements in small times which translate to huge power requirements.
>>6640047
This could all be summed up by saying, human like agility in giant robots imposes a scaling law where the power requirements scale proportional to the 4th power of the linear dimensions.
I'm dubbing this /sci/'s no-go theorem for giant robots.
>>6637951
Yeah, it's pretty lame to see these "humanoid" robots with their noisy geared servo motors, hobbling around like very old men who have just woken up.
Ranger, though not human in shape, is a big step in the right direction.
No one has yet written a program which can orchestrate a bipedal body's worth of muscles. It turns out that an action as simple as walking is a computational mountain.
>>6637720
Why should the robots be bipedal in the first place? Is that the more effective form for the robot to be?
>>6640079
>No one has yet written a program which can orchestrate a bipedal body's worth of muscles.
That is nonsense. Very good programs have been written in simulations. The big problem at present is hardware, and not of the computing type.
Our actuators are nothing like muscle and tendon. We've developed motors good for driving wheels, and adaptors for them sufficient to make heavy, stationary industrial robots. Hydraulics are similarly poor, heavy, complicated actuators. We don't have a suitable artificial muscle, or at least so far they haven't been available enough for researchers to build whole bipeds out of them.
>>6640047
Well what if we come up with lighter and stronger materials?
I wouldn't strike out the idea just because we don't have the tools yet.
The main reasons I think gundams as in anime will never exist are:
1. The energy requirements for such a machine.
2. The safety of the pilot. If the machine by any chance falls to the ground, the pilot will be a mess inside the cockpit.
3. The materials required to build it, vs the materials required to destroy it. I mean it will be as strong as it's weakest point. And once neutralized then you've lost all these materials to build it.
4. You would be a huge target.
5. Humanoid body is not more agile or faster than a cat like body.
6. The method of control. Even though it looks human like, it would be really hard to control by a human. That;s because the huge mass would make every movement slower. If you try to apply some kind of AI mechanism, then things become even more complicated than they are now. Besides, look at the movement of current bipedal robots. It's all stiff and jerky, we are just not there yet.
That said, I don't think it will be impossible to build in the future. But for now we could make a smaller prototype. It won't be the ultimate military machine ever, but it will be nice to have for construction work for example.
>>6640180
This
also op , try to think of something that overcomes all these problems
( tip : pic related )
>>6640105
>That is nonsense. Very good programs have been written in simulations
Can you show me some?
>The big problem at present is hardware, and not of the computing type
It's not hard to make a fully articulated hand. You wouldn't even need to know much about physiology or mechanics; using your own hand as a model for articulation, and anatomy pictures to get the scale and positioning of the bones and such right, a child could do it.
Hooking that up to a computer though, and getting the computer to use the hand in complex ways is a chore. Our robots manage such complex and fine manipulations *because they've been preprogrammed.* They don't have the computing power, or the programming to figure out how to use their 'bodies' in new, complex ways.
>Our actuators are nothing like muscle and tendon
>http://www.sciencedaily.com/releases/2013/05/130529092009.htm
>Traditional methods of electrochemically powered yarn muscles were destined to include slow responses, low strain and force generation, a short cycle life, and low energy efficiency. They were also in need of electrolytes, counter electrodes, and device packaging. Such requirements increase the weight of the actuator leading to a decrease in performance
>The 'Hybrid Carbon Nanotube Yarn Muscles' created by Kim however, has overcome such limitations by confining paraffin waxes, a thermally or electrothermally powered actuators, within the yarn. By doing so, the response rate is enhanced and a helical geometry enables both torsional rotation and tensile contraction
>Muscle contraction -- also called actuation -- can be ultrafast, occurring in 25-thousandths of a second. Including times for both actuation and reversal of actuation, the researchers demonstrated a contractile power density of 4.2 kW/kg, which is four times the power-to-weight ratio of common internal combustion engines
>https://www.youtube.com/watch?v=-KxjVlaLBmk
>High-Speed Robot Hand
You're right, they're better.
>>6640208
>http://www.sciencedaily.com/releases/2013/05/130529092009.htm
>2013
>new invention
>still not in production
>requires carefully arranged carbon nanotubes
>totally unproven beyond a microscopic scale
>https://www.youtube.com/watch?v=-KxjVlaLBmk
>low-force demonstration
>connected to large external power supply
>no relevance to the demands of bipedal walking
>>6640225
>still not in production
>http://www.materialsviews.com/mass-production-of-polymer-nanotube-composite-fibers/
>Karen Lozano and co-workers, at University of Texas—Pan American in Edinburg, Texas, showed in an article just published in the Journal of Applied Polymer Science a new way to make these composites which they believe can crack the code to strong, but cheap, materials for a variety of applications, particularly in energy storage, since the composites they produce have very good electrical conductivity as well
>requires carefully arranged carbon nanotubes
>http://www.technologyreview.com/view/507576/nanotube-muscles-bench-50000-times-their-own-weight/
>These carbon nanotube muscles can lift loads 200 times greater than natural muscles the same size
Even within the context the precision possible now, we can produce muscles and materials stronger then those used in biology. This simply isn't an issue; the lack of mass production is the main limit at the moment.
>totally unproven beyond a microscopic scale
>http://scholarship.rice.edu/handle/1911/18626
>The first ever macroscopic fibers, consisting entirely of SWNTs, were successfully produced and characterized
>2004
Is your information about this field *that* out of date?
>low-force demonstration
How about this gif then? Or the industrial robots which put cars together?
>https://www.youtube.com/watch?v=3CzuQ3DtsPc
>slapping a car together
This is all done by machines that don't even use carbon nanotube muscles - they use the older, usually hydraulic motors you were thinking of. Yet, the produce cars which no human hand could manage.
The mechanics aren't the obstacle.
>connected to large external power supply
And you're connected to an external food supply.
>no relevance to the demands of bipedal walking
Bipedal walking is an application of the same essential, mechanical engineering. We even have equations to model it.
>>6637892
>100cm^2, or 1m^2
100 cm^2 is 1 dm^2 not 1 m^2 new fag
>>6640302
Ugh, you're equating a bunch of things that are completely different.
>>totally unproven beyond a microscopic scale (talking about the carbon nanotube muscles invented last year)
>The first ever macroscopic fibers, consisting entirely of SWNTs, were successfully produced and characterized (talking about
non-muscle nanotube yarn)
The rest of your post is just more of this same kind of stupidity.
It remains a fact that we simply have not had suitable actuators for efficient, humanlike bipedal locomotion. I never said that they aren't under development or that we won't get them soon.
>>6637720
Perhaps, like in Evangelion, a biologic creature controled by robotic means would be a path to tall bipetal robots.
>>6640326
>Ugh, you're equating a bunch of things that are completely different
Not really.
>>totally unproven beyond a microscopic scale (talking about the carbon nanotube muscles invented last year)
>http://www.researchgate.net/publication/27260535_Carbon_nanotubes_acting_like_actuators/file/50463515a29fd06d56.pdf
>Macroscopic sheets of single-walled carbon nanotubes, working under physiological conditions (in salt water for example) and low voltage, have shown comparable or superior performances than natural muscle
>2002
Also, they weren't invented last year.
can we have zoids then
>>6640353
>posts link to entirely different actuator made from carbon nanotubes
>claims the one we were talking about "wasn't invented last year" because this completely different one was made sooner
>quotes "have shown comparable or superior performances than natural muscle" without actually reading enough to find out that they mean this in a very narrow technical sense
Yeah, I should have known this conversation wasn't going to get any better.
>>6640459
Yes. They'll be slow and impractical, but giant quadruped or hexapedal robots are infinitely easier to build.
Why go with bipedal? What advantage could they possibly have over multiped?
>>6640478
>posts link to entirely different actuator made from carbon nanotubes
The point was that you don't need carbon nanotubes to build a robot that has a human range of motion - the videos of various robots prove that.
The one reference was to prove that macroscopic actuators made of carbon nano tubes have existed since 2002 - a completely different claim of yours that's false.
>claims the one we were talking about "wasn't invented last year" because this completely different one was made sooner
I never made that claim - you're making that inference, and I don't think it was because of an honest mistake.
>quotes "have shown comparable or superior performances than natural muscle" without actually reading enough to find out that they mean this in a very narrow technical sense
Are we having the same argument? The only reason I posted a link to that particular paper was that it disproved your previous claims that carbon nanotube based muscles hadn't been manufactured on a macroscopic scale - not only had they been manufactured on a macroscopic scale, it was done twelve years ago.
>Yeah, I should have known this conversation wasn't going to get any better
Meh, at least you aren't swearing or calling me names.
>>6640516
>The point was that you don't need carbon nanotubes to build a robot that has a human range of motion
"Range of motion" isn't the problem. If your understanding of actuators is so simpleminded that you think a "human range of motion" is all you need to have the mechanical capabilities of the human body, you shouldn't talk about robotics.
>The one reference was to prove that macroscopic actuators made of carbon nano tubes have existed since 2002 - a completely different claim of yours that's false.
>your previous claims that carbon nanotube based muscles hadn't been manufactured on a macroscopic scale
A claim of mine that's false? More like a claim that only ever existed in your imagination.
I was talking about the specific actuator you linked, which was invented last year, which you then equated to a completely different actuator, which only happens to also involve carbon nanotubes.
If you can't keep this simple shit straight, maybe you should just not talk about any technology more complicated than a spoon.
>>6640488
>hexapedal
DUDE i know just what we can do.
with this, we would need low power for transport, but then we it battles, we might have an issue
then theres this :D
https://www.youtube.com/watch?v=0jyBiECoS3Q
>>6640531
>"Range of motion" isn't the problem
Yes, exactly. It isn't. We long ago acquired the capacity to make robots that could have any range of motion we wanted them to have. We just can't program them.
Do you even remember that this is what we were arguing about? Do you know that you're now agreeing with the very statement you originally disagreed with me on?
>A claim of mine that's false? More like a claim that only ever existed in your imagination
In >>6640225 you said;
>totally unproven beyond a microscopic scale
I then went on to post multiple sources which discussed macroscopic carbon nanotube constructs.
>I was talking about the specific actuator you linked, which was invented last year, which you then equated to a completely different actuator, which only happens to also involve carbon nanotubes
You claimed that the main obstacle to making bipedal robots is the mechanics. I proceeded to post an example of how carbon nanotube muscles not only had similar mechanical properties to natural muscle; they were superior. The muscles in question are macroscopic; a video displaying macroscopic application is available in the link I posted.
Not only that, but the videos of current industrial robots - using arms to manipulate steel with a precision and strength completely beyond human - prove that this level of strength, speed, and agility has existed for decades before.
Finally, I posted the link to the paper because it proved that carbon nanotube muscles weren't new technology.
>>6637892
Except, that, u know, u just can't have a 17.5m tall humanoid robot weigh just 58.1 tons
>>6637720
Power:weight ratio
We already got human-like bipedal robot but it does require huge amounts of energy to work.
/thread
Doesn't even look like power consumption is the problem
https://www.youtube.com/watch?v=wHLGqjoeLS0
I'd guess it's all about the programming. You can give them the muscles to move (which is also a huge challenge in its own right), but you need to tell it how to move.
Even in computer simulations that's a very hard thing to do, and one solution is just to run thousands of simulations with small changes until it eventually finds one that balances and allows it to walk (basically letting the movement algorithms evolve over generations)
>>6641530
>>A claim of mine that's false? More like a claim that only ever existed in your imagination
>In >>6640225 you said;
>>totally unproven beyond a microscopic scale
>I then went on to post multiple sources which discussed macroscopic carbon nanotube constructs.
Are you seriously going to drag this around in circles? In context, I was clearly referring to the SPECIFIC carbon-nanotube-based actuator you had linked, not to this general idea of "macroscopic carbon nanotube constructs" you fantasized that I was talking about.
>You claimed that the main obstacle to making bipedal robots is the mechanics.
It is, and your petulant equivocations don't change that.
>I proceeded to post an example of how carbon nanotube muscles not only had similar mechanical properties to natural muscle; they were superior.
You posted an example of a specific carbon nanotube muscle invented last year, and not yet in production (if indeed it ever will be, which is doubtful).
>The muscles in question are macroscopic;
Whether you call these threads "macroscopic" or "microscopic", they are very, very small, and by the mechanism they use, it is unlikely that they would work when bunched together into human-muscle-sized bundles. This is a scale-dependent technology, that needs to be able to heat up and cool down at tightly controlled rates. To make it into a human-scale muscle would take additional inventions. This is not available technology.
The other, more realistically "macroscopic" actuator may also be made using carbon nanotubes, but it works by an entirely different principle, and can only be said to outperform human muscle in an extremely abstract, narrow, technical sense. It is certainly not suitable for actual use.
>a video displaying macroscopic application is available in the link I posted.
The video about the hand uses yet another entirely unrelated actuator, which is high-speed, low-strength, and unsuitable for walking robots.
>>6641984
dat video doe
awesome find anon
>>6640508
>>6640488
>>6640191
m-m-m-muh beam sabers
>>6637720
power source........period
>>6640079
This isn't good enough for you?
https://www.youtube.com/watch?v=pgaEE27nsQw
>>6644572
Oh god, I love this video so much. Makes me want to program physical simulations.
For anyone in doubt of whether to follow that link, it's an animation of walking simulations. They show their fails along the way and other very amusing stuff.
>>6644572
That's actually exactly the kind of thing I had in mind in regards to solving the programming problem. Why bother doing the work yourself, when you can just write a program that writes it for you?
Still, it doesn't change the fact that even what's depicted in that video is a simplistic, limited form of movement. I'd like to see those things walk over the boxes that were being thrown at them, or climb a rope.
Personally, I think complex human movement is caused by certain 'firmware' loaded onto a very dense computer - the brain. The 'firmware' learns movement just like the program depicted in that video.
Writing an equivalent to the firmware is one thing - hooking it up to a computer which can deal with the amount of information produced by such a body is another.
>>6644588
highlight
>>6645350
>Takeshis_Castle.gif
>>6645346
>>Why bother doing the work yourself, when you can just write a program that writes it for you?
because we don't have the resources to break real world robots until the program learns not to.
It's also more valuable to get the algorithms down for whole body control so that we can apply to more than just one robot.
Also what is you neckbeard's obsession with artificial muscles for bipedal robots? Especially inefficient, and unscalable ones that use carbon nanotubes? Those carbon nanotube muscles use HEAT, heating stuff is a very inefficient way to produce mechanical work. And one has to remove this heat to get them to contract, limiting bandwidth.
And why would you need linear actuators in the first place? The motions one wants in a robot are almost all rotary. And with rotary actuators one gets a smaller force loop than one could ever achieve with linear actuators, meaning one can get less uncontrolled deformation/more precision.
The real advantage of artificial muscles is in things like robotic tentacles and shape-shifting robots.
Also, working on artificial muscles, ask me whatever.
>>6645370
Link to something like you're working on?
Had a BME friend show me how the cell stretches out years ago. Thought it was the coolest shit
>>6645372
Not really much to show yet.
But pic and link might be related:
http://opfocus.org/index.php?topic=story&v=2&s=5
>>6645370
>because we don't have the resources to break real world robots until the program learns not to
That's... kind of the point of doing it in a program?
>Also what is you neckbeard's obsession with artificial muscles for bipedal robots?
We want robots that move like people.
>Especially inefficient, and unscalable ones that use carbon nanotubes?
Firstly, because of their mechanical properties. Second, why do you think they're unscalable?
>http://www.nature.com/news/graphene-spun-into-metre-long-fibres-1.9549
>Nano-sized flakes of graphene oxide can be spun into graphene fibres several metres long, researchers in China have shown
>At the moment, the mechanical strength can’t compete with carbon fibres, but we believe that the mechanical properties can be greatly improved
If you look in the article, you can find macroscopic graphene thread wound around a spool - large enough to hold in your hand.
Allegedly, you can also make large batches of it now;
>http://www.nature.com/nmat/journal/v13/n6/full/nmat3944.html
>Scalable production of large quantities of defect-free few-layer graphene by shear exfoliation in liquids
>By fully characterizing the scaling behaviour of the graphene production rate, we show that exfoliation can be achieved in liquid volumes from hundreds of millilitres up to hundreds of litres and beyond. The graphene produced by this method performs well in applications from composites to conductive coatings
>And one has to remove this heat to get them to contract, limiting bandwidth
Graphene is one of the most thermally conductive substances known.
>The real advantage of artificial muscles is in things like robotic tentacles and shape-shifting robots
Why not.
>Also, working on artificial muscles, ask me whatever
What do you think of this;
>http://www.popularmechanics.com/science/health/breakthroughs/synthetic-muscle-made-of-fishing-line-is-100-times-stronger-than-the-real-thing-16514805
>>6645395
>>We want robots that move like people.
you can do that with rotary mechanical actuators.
>> unscalable?
heat dissipation. As one increase the volume of the muscle, the surface area to volume ratio decreases, decreasing heat dissipation capability.
While one could build a large version of this, more heat would be stored, but it would be harder to dissipate.
>>Graphene is one of the most thermally conductive substances known.
However, paraffin, which is needed for the actuators described above, not only has a low thermal conductivity, but a high thermal mass which further decreases response rate.
The nanotubes are mostly being used as a big fancy resistor. Wax motors are nothing new.
>>fishing line actuators
it's a heat engine and by carnot efficiency, a very sucky one
>>6645412
>you can do that with rotary mechanical actuators
That's what I was trying to tell >>6641997, but he wouldn't listen.
>heat dissipation. As one increase the volume of the muscle, the surface area to volume ratio decreases, decreasing heat dissipation capability
>While one could build a large version of this, more heat would be stored, but it would be harder to dissipate
Graphene and carbon nanotubes have thermal conductivities which are an order of magnitude higher then copper or silver.
It takes 1.355 joules to lift 1lb 1ft, or 8.13J to live 1lb 6ft. At 10-27% efficiency (I can't find a good reference), it would take 14,634J for a 180lb man to lift his own weight. That's 13,170.6J of heat.
A 'carbon man' would lose heat 10x faster then an object of identical shape made out of copper, and if I'm correct in assuming that human tissue has a W/mK of 1.06, then such a robot would lose heat about 5,000x faster.
>However, paraffin, which is needed for the actuators described above, not only has a low thermal conductivity
Couldn't that be solved by using graphene as a heatsink?
>but a high thermal mass which further decreases response rate
There are alternatives to paraffin - though I must admit there's a reason they use it - and you could probably do what I said about.
>The nanotubes are mostly being used as a big fancy resistor. Wax motors are nothing new
Well, then we're even closer then I thought.
>it's a heat engine and by carnot efficiency, a very sucky one
If you can get rid of the heat fast enough, and the muscles in question produce 4.2Kw/kg... there's not much more you could ask for. Even if your robot gobbles energy like pacman and doubles as a space heater.
>>6645495
>>10-27% efficiency
they are 1% efficient:
http://www.scientificamerican.com/article/artificial-muscle-advance/
>>thermal conductivity
Is often different for the bulk material.
>>Couldn't that be solved by using graphene as a heatsink?
No, you'd need active cooling, which is further going to decrease efficiency
Paraffin also has a heat of fusion of 200–220 J/g, so it stores a pretty decent amount of heat upon melting, that's quite a bit of heat to get rid of to cycle these muscles.
>>6645522
also, here's an exciting video of a wax motor:
https://www.youtube.com/watch?v=SmuDltaKPQQ
>>6637720
actuators, there are no good actuators,
though a bobcat hydraulic system comes close.
the other reason is every fcking robot builder never make a movable centre of mass in hte torso.
would need a spine or something similar so you can shift the center of mass fluidly.
Artificial muscles are discussed on biohackme im sure they could perform better than servos, although I don't know...O
>>6637720
Energy density for powerplants and engines are pretty good but not at that scale.
Scaling laws.
Actuator being rotating shafts instead of muscle-like
The human body have pretty fucking fancy multi-layer control(reflex pathway, spinal pattern generators, cerebellum and other nuclei and the motor cortex, all in a feedback loop from a huge amount of sensors.)
>>6645522
>they are 1% efficient
>An option for improving efficiency is to use a chemical fuel rather than electricity to power the muscles. "One way to compensate for a lack of efficiency is to use fuel like methanol instead of a battery," he says. "You could store more than 20 percent more energy in a fuel like methanol than you can in a battery
Though I was referencing biological muscle efficiency - which is about 10-27%.
To me, this is the real stickler;
>the latest artificial muscles are for the most part inefficient and limited in the combinations of force, motion and speed they can generate
>Is often different for the bulk material
We're dealing with macroscopic, hold-in-your-hand quantities. The differences between thermal conductivity on a microscopic level vs. a macroscopic level have already shown themselves.
>No, you'd need active cooling, which is further going to decrease efficiency
>Baughman says. "If you keep making the [carbon nanotube] yarn longer and longer, your cooling rate increases."
>Paraffin also has a heat of fusion of 200–220 J/g, so it stores a pretty decent amount of heat upon melting, that's quite a bit of heat to get rid of to cycle these muscles
How convenient that the same material you're using to make the muscles also has the highest thermal transfer ever seen.
boop
