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What is Pneumatic Artificial Muscle?

What is Pneumatic Artificial Muscle?

Do you remember the phenomenon learned in a science experiment in elementary school that, when the mouth of a syringe was closed, the piston was pushed and then the hand was released, the piston would return to its original position?

In this way, when air is compressed, a force is generated to return it to its original volume.

Pneumatic artificial muscle is a device that generates traction (pulling force) by utilizing the force of compressed air.

Push the piston in

Air in the syringe is compressed

Piston is pushed back as compressed air tries to return to its original state

Operating Principle of Pneumatic Artificial Muscle

An example of a typical pneumatic artificial muscle is McKibben-Type Artificial Muscle.

Pneumuscle is one of the McKibben-Type Artificial Muscles.

As shown in the right figure, Pneumuscle has a structure in which a rubber tube is covered by a mesh-patterned braided cord.


Since compressed air tries to return to its original volume, when applied to a rubber tube, the tube relaxes radially and axially as shown in the figure below.


Braided cords are often used in a tubular form, or braided in a spiral shape.

As shown in the figure below, the mesh angle changes, resulting in a structure that increases in diameter when pushed into the axial direction and decreases in diameter when pulled.

【English】スリーブ 収縮.png

When compressed air is applied to the rubber tube, the radial relaxation of the rubber tube changes the angle of the braided cord, which generates an axial contraction force.

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