How to make air muscles!

Step 1 Materials

All of the materials are readily available on Amazon.com, with the exception of the 3/8" braided nylon mesh- it is available from electronics suppliers. Amazon does sell a braided sleeving kit with several sizes of braided mesh but the exact material is not stated-
Amazon

You'll need an air source:
I used a small air tank with a pressure regulator but you can also use a bicycle air pump (you will have to make an adapter to make it work with the 1/4" poly hose.
Air tank- Amazon
Pressure regulator (will require a 1/8" NPT female to 1/4" NPT male adapter)- Amazon

1/4" high pressure poly tubing- Amazon
multitool (screwdriver, scissors, pliers, wire cutters)- Amazon
lighter

for the small muscle:
1/4" silicone or latex tubing- Amazon
3/8" braided nylon mesh sleeve (see above)
1/8" small hose barb (brass or nylon)- Amazon
small bolt (10-24 thread by 3/8 in length works well)- Amazon
steel safety wire- Amazon

for the large muscle:
3/8" silicone or latex tubing- Amazon
1/2" braided nylon mesh sleeve- Amazon
1/8" or similar sized drill bit- Amazon
21/64" drill bit- Amazon
1/8" x 27 NPT tap- Amazon
1/8" hose barb x 1/8" pipe thread adapter- Amazon
small hose clamps- Amazon
3/4" aluminum or plastic rod to construct the muscle ends- Amazon

Safety note- make sure you wear safety glasses when testing your air muscles! A high pressure hose that pops off a loose fitting could cause a serious injury!

Comments

[Salsa766]

 is that the leatherman juice s2?

[Honus]

Yep!

[Deus Tempestas]

I had a dead power supply from a computer, the main mass of wires had a braided nylon mesh tube around them. 0$

[jnordstrom]

What is the best way to accurately control a set of opposing mussels, example human leg, I have been researching 2/3 way solenoids and IO controllers connected to a PC. Should I use two 2-way solenoids per mussel, one to let air in and the other to let air out, 3 way solenoids let all of the air out, I assume one would want to let only some of the air out for precise control. Also how do I partially inflate/deflate the mussel, using timing? E.g. open the solenoids for 0.10 seconds, 0.20 seconds, I assume an electronic PSI controller e.g. fill the mussel with 20 PSI, now 25 PSI etc would be better, does such a thing exist?

[toohuman]

The problem with this muscle actuator type is that it's impossible to develop control systems anywhere near as good as a the dozens of force pairs and thousands of recruitment patterns that a human extremity contains. Add that to the fact that the actuator isn't self contained and you've got a fun toy with no real chance of being an effective actuator for prosthetics.

[jnordstrom]

I am working on building a full size humanoid with similar but simplified human mussel movement and simplified (more traditional robot) joints. The PSI of both the input and the output must be controllable, controlling how fast the mussel will contract and release. The solenoids seam to only support fill or vent (I don’t understand the hold part of a solenoid, I only see fill and vent?), I could use short burst at 60PSI but that creates unnatural jerky movements. I guess what I need is a digitally adjustable regulator? I think that would solve the issue. So for slow movements I would say fill at 20PSI until you reach 20PSI. For fast movements I would say fill at 60PSI until you reach 60PSI. I hope I am using the right terminology I’m assuming flow rate and PSI are synonymous. These could also be combined, when moving a leg or arm, move quickly until near the destination then move slowly. Or fast, medium to slow. There must be products like this with all of the industrial uses of air. Thoughts?

I found a pressure sensor but it does not support 60PSI and does not do totally what I wanted.

http://www.trossenrobotics.com/store/p/3226-Pressure-Sensor.aspx

For the controller I plan on using several InterfaceKit 0/16/16 from Trossen Robotics connected to an AMD quad core with 8GB RAM. I plan on writing the controller code in Java using the drools rule engine.

http://www.trossenrobotics.com/store/p/3201-InterfaceKit-0-16-16.aspx

[Honus]

You might check out Festo's website: http://www.festo.com

They have all kinds of valves and controllers and they built a really incredible pneumatic arm.

[jnordstrom]

Great site I'm digging through the product catalog, and thanks for the previous links, very informative. I did find one item that may offer the precise control I was looking for http://www.controlair.com/transducers/900trans.html

[Honus]

You would probably have to use 3 way solenoid valves and connect them to a microcontroller with a pressure sensor installed at the end of the air muscle. The pressure sensor would tell the microcontroller when a desired pressure is reached and then the microcontroller would tell the valve to either fill, hold or vent. I'd imagine you would need to interface the microcontroller with a computer to be able to make it all work together. A lot of large movie animatronics are controlled this way using hydraulics with the computer telling the controller which valves to open and when. I have yet to do anything like this but you could probably do it using MAX/MSP or Processing and using an Arduino or MAKE controller.

http://www.cycling74.com/products/maxoverview
http://processing.org/
http://www.arduino.cc
http://www.makingthings.com

[jnordstrom]

I like the aluminum rod as it looks like it would provide a proper seal and be strong, the piece is no longer available on Amazon can you recommend another provider?

[Honus]

There are lots of online metals suppliers- try here:
http://www.onlinemetals.com/merchant.cfm?id=195&step=2&top_cat=60

[l96470fps]

great job !! but will inner tube work??

[Honus]

If it's a latex inner tube it might. I don't know about a butyl rubber inner tube- give it a shot and see what happens.:)

[bombmaker2]

is 3/8" the id or od

[Honus]

It's 3/8" OD. If you have any other questions just let me know.