Alcohol Powered Muscles

ianchaos writes "In an article on ScienCentral News, Scientists at the University of Texas are using alcohol to power artificial muscles. From the article: 'Usually the only alcohol-powered muscles are the ones in barroom brawls, but one scientist is adding alcohol to artificial muscles to power robots and more.'"

Comments

My artificial muscle dream...

[foniksonik]

For many years I've thought of a mechanism for artificial muscles which didn't perfectly mimic either natural muscles, arthropods (hydraulics) or typical electrical motor joints.

It's based on the idea of muscles, that they exist in perpetual tension, so that to create motion via contraction you don't create more tension on one side of the bone, instead you simply relax the tension on one side and allow the existing tension on the other side to fully exert itself.

One way of achieving this would be to use thousands of taut wires each attached at one end to the 'bone' via a ligament like structure that would reinforce them... basically you could just braid them all together near the attachment point, and also attached to a motor that would wind or unwind them along it's circumference... thereby tightening or loosening the 'muscle'. This first muscle would be counterbalanced on the opposite side of the bone by a muscle with attachment points inverted, so that for an arm there would be a motor at the elbow and one at shoulder, each controlling one muscle in the arrangement. By rotating each motor only slightly for the degree of motion desired, you could pivot the arm at the shoulder with the strength and force of the movement only limited by the tensile strength of the materials used. By keeping the muscles under tension 'while at rest' there would be a very fast reaction time, similar to any spring based mechanical movement... think hard drive coil... ie: very fast quick twitch response... and at the same time the tension would also provide stiffness and immediate torque for heavy lifting type movements.

I'm sure other more sophisticated arrangements could be conceived, some using hydraulics or next gen materials like this memory wire... but the point is to use constant tension to produce very controlled, precise, quick, strong movements or long elastic fluid movements as desired... rather than no tension single point of torque/force which leads to poor control, etc.

my 0.2 on artificial muscles

Re:My artificial muscle dream...

[zopf]

For your concept to work, the "wires" would have to have some sort of reasonable spring constant that would allow you to set up a constant tension of your choice in them. To wind these tightly enough to make them have relatively constant length under a certain level of stress, a system would need a motor/gear system capable of producing high torque. Unfortunately, the system would have limitations. It could never apply a constant force, as the force it produces is related to the displacement (extension) of the "wire", and as it shortens, the force becomes less (assuming it behaves as a fairly ideal spring). It would also be difficult to control the velocity of the spring without using the opposing motor or some other active damper (which require more energy). Basically, the idea you have is what the medeival engineers called a catapult - you wind it up with some sort of crank and then let it go and see what happens. It could be useful for some things (like throwing objects), but might be difficult to control, and offers relatively few advantages over conventional systems.

Not really about alcohol...

[mattmacf]

From TFA:

In one experiment, Baughman used alcohol to fuel the movement of these artificial muscles. His team coated the shape memory wire with a chemical called a catalyst. When alcohol was added, it reacted with the oxygen in the air, burning up and releasing heat.

While the whole alcohol bit makes for a great article, the technology is really in the wire. The only purpose for the alcohol here is in an exothermic reaction that causes the memory wire to heat up and contract. Don't we already have a million ways of doing that that don't prompt the requisite Futurama jokes?

I also fail to see the promise in this technology. It apparently has its advantages over fluid power (at least enough to warrant researching), but lacks reliability and efficiency? A quick venture to Wikipedia tells us "these materials are not currently appropriate for applications such as robotics or artificial muscles, due to energy inefficiency, slow response times, and large hysteresis." AFAICT there are still far too many questions keeping this tech from prime time.

For instance, how many contractions do you get before the material is exhausted? Is it like a rechargable battery where after a certain number of contractions you get ever diminishing returns from the wire?

What effect do the chemical reagents have on the physical properties of the wire? Is there a pair of exothermic reagents that will not corrode or degrade the wire over the long term?

What about the strength of the wire? Can you accurately fine-tune it to exert a controlled force over a given distance? What about releasing the tension in the wire? Would that require another force acting in an opposite direction, or do you just have to wait for the wire to cool off?

Sounds cool. Just not terribly promising.

Re:Not really about alcohol...

[Anonymous Coward]

I also fail to see the promise in this technology

Do you have absolutely no imagination? By those standards, flesh and blood-powered muscles are also pretty damn terrible. Flesh muscles are slow, get tired and aren't particularly efficient. Except that the technical problems with the artificial muscle are eventually going to be solvable.

My point is that because these muscles are similar in operation to human muscles, they're an interesting branch of technology that could one day enable building humanoid robots that work just like we do. The best way to function in an environment designed for humans - is to be designed like a human. Not to mention replacement limbs and cybernetic enhancements that could integrate well with human bodies.

Is that a promising enough vision for you?

Seeing as we've exhausted Futurama...

[Will2k_is_here]

Here's some Simpsons:

"One for you, one for me. One for you, one for me."