Experimenting with an air muscle and sensor feedback

Check out this setup that [Ruenahcmohr] is using in his air muscle experiments. The orange mesh contains an air bladder that is connected to a hose on the right side. The bladder can be filled, or emptied with two solenoid valves not seen here (but you can get a good look in the video after the break). The muscle attached to chain on the other end and is kept under constant tension by a spring. The chain bends 180 degrees around a gear which is connected to a potentiometer. This gives feedback to the ATmega32 which controlling the whole thing. This way, the slider seen above can be used to control the apparatus.

We don’t know if [Ruenahcmohr] has a use in mind for this setup, but it certainly looks promising! We’ve seen these air muscles used for haptic feedback before, but right now we’re drawing a blank when it comes to ideas. What would you use it for?

[Thanks Zhanx]

29 thoughts on “Experimenting with an air muscle and sensor feedback

  1. I guess we better make sure those 3 laws are in place…

    Seriously though, I can’t come up with any use for this. You would need a portable air system and that makes it to impractical!

    1. The portable air system isn’t a problem when its on a 12′ mecha. I don’t expect you to belive me }:)
      Funny enough, it works out to only need about 2HP, I’m told (by zhanx) that 2 AC compressors shouldn’t have a problem with that. The budget for this is $240, so the airmuscles are part of the money saving scheme.
      I’M SEEKING: 47 clothes washing machine and 94 dish washer water control valves! 12′ robot has lots of space for donation credits! :)

          1. Not trying to sound rude but, what do you mean “you sure none of the peices are too small”? I do not under stand~

  2. The company Festo has a line of air muscles.
    They have a demo racing chair whit six degrees of freedom.
    The use of these muscles makes it a very natural and fluent ride compared to setups that use electric or hydraulic actuators.
    They forgot to bolt it to the flour though.
    That was fun when I deliberately crashed into a wall on the sim. :p

  3. This is nice. I could see this being used in many industrial applications where hydraulic oil leakage would be bad, and the associated EMF from solenoids would also cause problems. Compressed gas systems using Compressed Air Controls- very old technology (US Navy subs used CAC for HVAC controls many decades ago)- noise might be an issue unless silencers are used, but one again, low tech. The simplicity of designs plus the lack of electronics and lack of hydraulic liquids makes this a dead ringer for developing countries needing industrial applications of this sort. Yes, air is a fluid- hence why I stated hydraulic liquids.

  4. Ah! About time this genius gets on HAD =)

    His plan is to build a huge robot using these air muscles. I’m unsure if the robot is to be an humanoid or something else, but it’s gonna be huge. It’s gonna need over a hundred of those muscles.

    #robotics on FreeNode is where you can find him.

    1. yes, but to do that, I need to measure force output of the muscle, I’m working on making some force sensors now. when I have that working I can have the microcontroller balance forces to get target positions. The spring was not intended to be permanent, its just for an initial testing stage.

  5. I agree with Jean above, a muscle by itself isn’t that great but when combined with a 2nd muscle, real work can be done.

    Oh and I would great a giant noisy bi-ped or quadruped robot possibly like the MIT cheetah robot but cheaper

  6. Force output of the muscle should be proportional to the air pressure. Easy to measure that. Maybe not cheap but should be easy to find a sensor.

    1. correct, pressure is proportional to force, but I can make a force sensor for less than $1, I’m not aware of a pressure sensor capable of 60psi that compares.
      Anyone want to help me asseble 188 force sensors?

  7. I read the comments and ideas you guys have. I have been doing research on “air muscles for a bit, but I cannot find step by step instructions on controlling a robotic arm using air muscles with potentiometers, like shown in this video from [Ruenahcmohr]. It is probably something so easy that I will think im an idiot for not thinking of it. So if some one has these step by step instructions please enlighten me on how to build it.

    1. I’m more than happy to share all of my work (heh, its play, dont tell) you can catch me live in the #robotics channel of the freenode irc server network. If you grub thru http://ruemohr.org (no www!) you may find hints, I’m happy to put togethor howtos of the things I’v done.

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