Society of Robots - Robot Forum
Mechanics and Construction => Mechanics and Construction => Topic started by: WriterOfMinds on March 09, 2014, 10:38:37 PM
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Some of you are probably already aware of the discovery that hit the news a few weeks ago -- researchers at the University of Texas learned that appropriately coiled nylon monofilament line could be used to make heat-activated artificial muscles. I'm trying to duplicate their work as a hobbyist. You can follow the results so far at http://writerofminds.blogspot.com/2014/03/homemade-artificial-muscles-from.html (http://writerofminds.blogspot.com/2014/03/homemade-artificial-muscles-from.html) I've successfully made some coils and gotten them to respond to heat. Has anyone else tried to make these muscles yet? Tips, questions, and discussion of your own tries at this type of muscle are welcome.
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I have not tried this but I am extremely curious about it. This has been popping up on a number of my news feeds. I have yet to see anyone relate their experience with it as a hobbyist. I'm particularly anxious to hear how people will heat these electrically without using a heat gun like in the demonstration. This could definitely have some exciting applications.
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A single strand of copper magnet wire twisted into the muscle will do, it appears. I can see that the tricky part will be getting the current right -- I just ruined a muscle with too much heat.
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My main question is how quickly you can relax the muscles after contraction?
Heat doesn't dissipate very quickly in air.
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Sorry for taking so long to respond. The cooldown time depends on the thickness of the nylon filament, and possibly also the compactness of the coils. The thin (I'm guessing 380 um) filament that I was working with at first returned to its original configuration within a few seconds after being heated, if I remember correctly. I'm working with some 711 um filament now, in a tighter coil, and it takes quite a while to relax after heating -- 10 seconds or more. I'll try to do some better characterizations and supply actual measurements later, but I haven't had much time to work on the project this week.
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I've got another official update on this, finally. I was able to get one of my muscles to contract and relax with electrical heating. http://writerofminds.blogspot.com/2014/03/its-time-for-some-updates-on.html (http://writerofminds.blogspot.com/2014/03/its-time-for-some-updates-on.html)
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Another update, and this one has videos of working muscles! I also discuss the different types of heating element that I tried out. http://writerofminds.blogspot.com/2014/03/diy-fishing-line-artificial-muscles-iii.html (http://writerofminds.blogspot.com/2014/03/diy-fishing-line-artificial-muscles-iii.html)
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I've been wondering if someone could build these muscles on the inside of a tube, and run hot/cold oil or water through the tube to contract/expand. At the top of the tube, you'd have entry of both a hot-oil and cold-oil recirculating system, and you'd use a vent to let one or the other in to expand/contract.
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Another update, finally! http://writerofminds.blogspot.com/2014/05/homemade-artificial-muscles-iv.html (http://writerofminds.blogspot.com/2014/05/homemade-artificial-muscles-iv.html)
The muscles are getting pretty good. I think I'm almost ready to build some for an actual application.
@jwatte: The original university research team did do a hot water/cold water setup, with some impressive results: they lifted 30 lb. with a bundle of four muscles. See one of the videos here: http://io9.com/scientists-just-created-some-of-the-most-powerful-muscl-1526957560 (http://io9.com/scientists-just-created-some-of-the-most-powerful-muscl-1526957560)
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Work on the artificial muscles continues. I have an update planned for tomorrow with some data on how much weight they can lift and how far, but before I get to that, there's some little stuff. First, I made a gigantic muscle out of nylon trimmer line, and it worked -- further expanding the possibilities for making these at home. Second, I have some observations and speculations about why the coils of the muscles sometimes "flatten." http://writerofminds.blogspot.com/2014/08/homemade-nylon-artificial-muscles-v.html (http://writerofminds.blogspot.com/2014/08/homemade-nylon-artificial-muscles-v.html)
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And here's the promised update with the muscle characterization data. http://writerofminds.blogspot.com/2014/08/nylon-fishing-line-artificial-muscles-vi.html (http://writerofminds.blogspot.com/2014/08/nylon-fishing-line-artificial-muscles-vi.html)