Artificial Muscles Use Carbon Nanotube Sheets

carbon nanotube being turned into aerogel sheet

Light as air, stronger than steel and more flexible than rubber. Sound like something from the next installment of the Iron Man series? [Tony Stark] would certainly take notice of this fascinating technology. Fortunately for us, it does not come from the studios of Hollywood, but instead the halls of the NanoTech Institute at the University of Texas.

Professor [Ray Baughman] and his team of scientists at the NanoTech Institute have developed a type of artificial muscle through a process of making aerogel sheets by growing carbon nanotubes in a forest like structure. Think of a vertical bamboo forest, with each bamboo stem representing a single carbon nanotube. Now imagine that the individual bamboo stems were connected together by much smaller horizontal threads. So that if you dislodge the bamboo and began to pull, the threads would pull the others, and you would get this sheet-like structure.

These aerogel sheets of carbon nantubes have some truly science fiction like properties. They can operate from 1,600 degrees centigrade to near absolute zero. If you inject a charge, each nanotube will be repulsed from one another, expanding some 220% of the sheet’s original size. Your muscles do this at roughly 20 – 40%. Stick around after the break for a video demonstration of these carbon nanotube aerogel sheets being made and demonstrated.

Thanks to [Steven] for the tip!

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Researchers Create Synthetic Muscle 100 Times Stronger Than the Real Thing

synth-muscle-02-de

A team of researchers at the University of Texas at Dallas have come up with an ingenious way to make a low-cost, high strength, artificial muscle. Their secret? Fishing line. The study was just published today in the journal Science, and the best part is they describe how to recreate it at home.

To create it, the researchers take regular fishing line (polyethylene or nylon string) and twist it under tension until it curls up into a tightly formed spring. It can then be temperature treated to lock in this position.

When heated again, the plastic tries to untwist — the peculiar thing is, this causes the entire coil to compress — think of it as Chinese finger-trap. Polyethylene and nylon molecules also contract lengthwise when heated. It can contract up to about 49%, with as much pulling power as 100 times its equivalent human muscle in weight. This equates to about 5.3 kilowatts of mechanical work per kilogram of muscle weight — similar to the output of a jet engine.

Stick around to see the video of how to make it — we’re excited to see what you guys think up for project applications!

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biological-inspired robotic eye movements

Researchers at Georgia Tech have developed a biologically inspired system to control cameras on board robots that simulate the Saccadic optokinetic system of the human eye. Its similarity to the muscular system of the human eye is uncanny.

Joshua Schultz, a Ph.D candidate, says that this system has been made possible in part to piezoelectric cellular actuator technology. Thanks to the actuators developed in their laboratory it is now possible to capture many of the characteristics associated with muscles of the human eye and its cellular structure.

The expectation is that the piezoelectric system could be used for future MRI-based surgery, furthering our ability to research and rehabilitate the human eye.

[via engadget]

DIY EMG uses an audio recorder

[Ericdsc] is looking to capture the electrical impulses of his muscles by using an EMG. He went through several prototypes to find the right recipe for sensors to pick up the electrical signal through his skin. Above you can see the version that worked best. Each sensor is made starting with a piece of duct tape and laying out a patch of stripped wire on it. A 5cmx1xm piece of aluminum foil then covers this, and second smaller piece of foil covers the cable’s shielding (not pictured here). This will stick to your skin to hold the sensor in place after applying a dab of sugar syrup to help make a good electrical connection.

In this case, an audio recorder is taking the measurements. [Ericdsc] had been having trouble sleeping and wanted to find out if he’s restless in bed. The audio recorder can log hours of data from the sensors which he can later analyze on the computer. Of course, it wouldn’t be hard to build your own amplifier circuit and process the signals in real-time. Maybe you want to convert that mind-controlled Pong game over to use abdominal control. You’ll have a six-pack in no time.

Electro-active polymers

What’s that you say? You’ve got rigid materials that change their shape when exposed to electric current? Sign us up for some! Although the fabrication process looks a bit daunting, we love the results of working with electro-active polymers. These are sheets of plastic that can flex by contracting in one direction when the juice is turned on. It has an effect very similar to muscle wire but distributed over a larger area.

From what we saw in the video after the break it looks like this is not the most resilient of materials. Several of the test shots have broken panes, but we’re sure that will improve with time. It looks like there is some info out there about fabricating your own EAP but the processes seem no easier than what’s going on at the research level. We might stick to building our own air muscles until EAP is easier to source for projects.

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Inventing robot athletes

The human body is an amazing instrument from an engineering standpoint. Replicating just one part of it proves extremely difficult but these athletic legs show a lot of promise. This is the work of a Japanese researcher named [Ryuma Niiyama]. He’s been working on the design for years, and is now using pneumatic actuators to mimic the muscles in a human leg. The lower portion of the leg uses a spring mechanism that resembles some running prosthetics currently in use. These serve as a spring to store energy and reuse it by bouncing against the ground. He’s trying to teach his robot to use these legs; taking it through a learning process necessary to use the thigh actuators for locomotion and balance. We were surprised at how life-like the motion in the video after the break is. Even when falling down the movements are very life-like.  We thought the movements of Little Dog were real enough to be creepy, and this robot may be close enough to our own mannerisms to fall into the uncanny valley.

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Ecce Robot

According to the video, Ecce Robot is a new paradigm in robotics. We don’t know if that’s true or not, but we really enjoy the drive system. They have mimicked the biological structures in humans using elastic cables and cheap drill motors as muscles. It is intriguing to watch the complexity that even a simple arm lift requires. This does show inefficient this type of set up is, but we still think it is cool. We don’t understand the desire to use cheap drill motors though. Cost aside, the control problem they mention seems like it could be resolved with a little better motor setup. Then again, we’re sure they thought of that. This seems like a perfect time to bring up a common question. Is it worth the inefficiency of trying to mimic our natural biological structures with hobby robotics pieces? What technology would have to be present to make it worth the complexity?

[via Engadget]