Project:Air Muscles

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What are they?

Air muscles are soft pneumatic actuators invented by a guy named McKibben in the 50s (they are sometimes named McKibben muscles). They have various qualities that make them useful for assistive robotics (and for hacking):

  • Very light and yet powerful(can lift dozens of time their own weight)
  • Interesting nonlinear behavior that makes them closer to the way biological muscle behave
  • Quite safe (no high voltage, "soft" dynamic behavior)
  • Easy to make yourself
  • Very cheap materials

They also have a few drawbacks:

  • They are air muscles so you need a compressed air source (usually a tank similar to those for scuba diving, sometimes smaller ones)
  • You also need all sort of valves and pressure regulators, and three-way solenoid valves if you want to slave them to some electronics. They can come a bit expensive.
  • The muscle only works when contracting, so you need two opposite muscles to make anything go both ways (like for biological muscles)
    • Or you can use one muscle + one spring, like on Adrian's demonstration/test device
  • Quite short lifetime (from some reports)
  • Rather slow response (from some reports, may be fixed by higher pressure and/or better air flow control)

What do people do with them?

  • Exoskeletons [1] [2]
  • More exoskeletons [3] [4] (well, there is no "skeleton" on this one, "muscle suit" would be more accurate)
  • Robots [5]
  • More robots [6]
  • The totally awesome Shadow Hand (made by a company here in London)
  • Ian found that: [7], the mould is 3D-printed and the actuator is cast silicon.

The list is in no way exhaustive and there is a large body of scientific literature on the subject.

What's the project?

User:Endy wants to make some kind of exoskeleton, but nothing is fixed yet, and it will require preliminary exploratory work with the technology.

Other members have shown an interest on the ML [8] [9]. Feel free to add yourself here if you want to be kept up to date:

How do you make air muscle?

See instructables here and there].

There are many other tutorials mostly on robotics forums (google [air|McKibben|pneumatic] muscles).


Please put links if you find good suppliers

Roughly put

  • Pressure regulator
  • Various adapters and connectors, hose clamps, etc.
  • Regular high pressure plastic tubing
  • Braided nylon mesh sleeve
  • Silicone or latex tubing
  • Hand valves (for testing) and/or three-way solenoid valves (+arduino)


  • We will obviously need an air tank and at some point a compressor. I found that: Pledge:_Compressor, it dates back to one and half year. Do someone know if the compressor was bought and if yes were it is ?