Great Animatronic News.

David Boccabella

Hi Folks.
I always keep my eyes out for possibilities and this article may be the holy grail for us creators.

http://engineering.columbia.edu/news/hod-lipson-lifelike-robots

Now - to cut to the quick.. This shows how to create artificial muscles from PlatSil in a way that anyone can do it.

Here is the Formula and Process.

Take 2 part PlatSil (They used Ecoflex 00-50) and mix into each part 20% of Ethanol.  Keep mixing until all of the Ethanol is incorporated in to the PlatSil.

Next wind a small coil of Ni-Chrome wire. Mix A:B together and encapsulate the coil in it. Let set.

Apply a voltage to the coil and let it heat up to approx 80C - you will see the PlatSil expand. Remove the voltage and it will return to the original size.

Principle..
By mixing the Ethanol into the PlatSil you form little 'bubbles' of Ethanol. When the Ethanol is heated above it's boiling point it vaporizes and so expands the 'bubbles' stretching the silicone and creating a muscle.
Removing the voltage caused the temperature to drop and so condense the Ethanol back to a liquid shrinking the silicone.

There is still a lot of development to go but this is a great way to experiment with artificial muscles that could be used in situations like facial movements etc.  Some ideas come to mine re would a lower vaporising liquid work (Hexane, Pentane). What about conductive thread etc.

Hope this gets some idea's running.
Dave

Chris Ellerby

Very cool stuff.  I've been following this subject for over a decade, and sadly the progress has not been super great yet.  The challenge is the speed, strength, and accuracy of these is just not there yet.  But hopefully in another 10 years they'll be a bit closer!

/Chris

Jeffrey Warren Park

The problem I see most in this concept, is "thermal fatigue" of the materials used. Also, the residual heat build-up would quickly make whatever mechanism it was used in to progressively lose efficiency. Until, it eventually comes to a virtual stop, until it cooled down, again. (This is also the limitation of "Nitinol" wire.) Add, to that, the eventual rupture of the "Ethanol bubbles" would cause increasing failure.

And, the more volitile the "vaporizing liquid" used, the more likely something may catch fire and/or explode. And, you wouldn't want to use a fluid that directly attacked the silicone, being used as the "carrier".

Overall, I think this concept is not feasible.

Jeffrey Warren Park

The irony in trying to replicate all the properties of living flesh, is it is nearly impossible. Even though living tissue seems to be amazingly strong, it is actually quite delicate. It is constantly being repaired & replaced, at the same time it is being utterly destroyed.  This is the basis of "building muscles through exercise". It is the result of the body's reaction to the damage caused by applied stress. No current synthetic material is capable of that, at this time. So, the best we can accomplish, currently, is a temporary illusion.

Until we can master "self-replicating/self-repairing" synthetic materials, we will not surpass the properties of nature. Mother Nature still has the advantage, (...so far).

David Boccabella

Hi all.
Research is progressing regarding artifical muscles. 
The Keplinger Research Group has been working on a inexpensive muscle called a Peano-HASEL.

Current stage of development is that it requires a high voltage to generate the electrostatic charge, but a new version has significantly reduced the voltage needed.

HASEL stands for (Hydraulically Amplified Self-healing ELectrostatic) actuators, can generate powerful linear contraction, operate at high speeds, and demonstrate high optical transparency. Additionally, these soft devices can simultaneously function as actuators and sensors that are capable of precise and life-like movement while self-sensing their position. Peano-HASELs are constructed from inexpensive thin-film plastics, the same material chip bags are made from. Currently, actuators can be made in the lab for less than 10 cents per device, using industrially compatible fabrication methods.

Highlight video of HASEL technology: https://youtu.be/YGMyW6AESsQ Publication in Science Robotics: https://doi.org/10.1126/scirobotics.a... Learn more about how HASEL works: https://youtu.be/M4qcvTeN8k0 Publication of fundamentals of HASEL in Science: https://doi.org/10.1126/science.aao6139 Keplinger Research Group: http://www.keplingerresearchgroup.com/ College of Engineering and Applied Science at CU Boulder: https://www.colorado.edu/engineering/ Mechanical Engineering at CU Boulder: https://www.colorado.edu/mechanical/ Video produced by Tim Morrissey: https://youtube.com/c/TimMorrissey

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