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Author Topic: A good use for muscle wire?  (Read 3516 times)

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Offline ShagsTopic starter

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A good use for muscle wire?
« on: February 26, 2008, 05:53:34 PM »
I know muscle wire is really not a favorite by most here at SOR but I think I may have a good use for muscle wire and wanted to see what some of the members thought.

A few of the members were planning or were in the process of building flying bots.  What about in a helicopter design using muscle wire to deform (rather than rotate) the blades.  one could set it up so as the shaft rotates it comes into contact with a charged cylinder (stationary).  This cylinder when charged transfers current into the main rotor system which then charges a short piece of muscle wire to deform the flexible blade into a lifting position.  This would save the use of a lot of moving parts and perhaps make the system less likely to break down because all of the mechanical work would be spinning the blade.  You wouldn't have to worry about addional control wires and servos to control actually rotating the blades.

Now here's where the veterans come in.  How quickly does muscle wire tend to change its shape and how strong does it actually pull?  If anyone has a link to some specifications for muscle wire that would be awesome.

Just an idea I had running through my head.

Matt (aka Shags, hey you have to keep at least one nickname)

Offline gamefreak

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Re: A good use for muscle wire?
« Reply #1 on: February 29, 2008, 09:48:25 PM »
im no veteran, but I do know that its speed can only be as fast as it can cool/heat, also maintaining a constant heat on the muscle wire could cause damage to it. Now with a high speed rotor cooling may not be a problem. I also think muscle wires dont have much torque, and in order to move the blades up/down while spinning at a high RPM may require a significant amount of it.

One use i've thought of is for small bipeds, but I dont think they have enough torque, and colling would be an issue.

Woot I love wikipedia, I found this SMA robot: http://www.lararobot.de/

The germans beat me to it, building an SMA robot, pfft. Although it isnt very elegent...
« Last Edit: February 29, 2008, 09:52:57 PM by gamefreak »
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Offline Soeren

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Re: A good use for muscle wire?
« Reply #2 on: March 01, 2008, 04:54:12 PM »
Hi,

"Muscle wire" won't do for a 'copter, far from.
I'm not biased away from it, but planning extensive use of it for facial muscles in an animated head/animatron, since it's the only way to get room for enough individual muscles (plenty of them in our flesh & blood variety).
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline Admin

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Re: A good use for muscle wire?
« Reply #3 on: March 09, 2008, 10:46:36 AM »
An SMA is only good for about 1000 deflections then it needs replacement.

Quote
How quickly does muscle wire tend to change its shape and how strong does it actually pull?  If anyone has a link to some specifications for muscle wire that would be awesome.

Datasheets:
http://www.societyofrobots.com/robot_faq.shtml#read_datasheet

Knowing those numbers, do the math to see if its strong enough:
http://www.societyofrobots.com/mechanics_statics.shtml


search google to find SMA's . . . also:
http://www.robotstore.com/
http://www.robotshop.ca/


The general rule of thumb is, beyond simple force calculations, is don't use SMA's for actuating anything that weighs more than a few grams at most.

 


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