The McKibben Artificial Muscle is a pneumatic actuator which exhibits many of the properties found in real muscle. Its spring-like characteristics, physical flexibility, and light weight make it ideal for applications such as the Anthroform Biorobotic Arm Project. The device was first developed for use in artificial limbs in the 1950's and, more recently, was commercialized in the 1980's by Bridgestone Rubber Company of Japan for robotic applications. The current configuration of the device was engineered by Dr. Jack Winters for the construction of accurate musculo-skeletal models. Some of the first commercial uses of this muscle will be in our robotic cat appendages!
The device consists of an expandable internal bladder (an elastic tube) surrounded by a braided shell. When the internal bladder is pressurized, it expands in a balloon-like manner against the braided shell. The braided shell acts to constrain the expansion in order to maintain a cylindrical shape. As the volume of the internal bladder increases due to the increase in pressure, the actuator shortens and/or produces tension if coupled to a mechanical load.
Image used with permission of the University of Washington Biorobotics Lab.
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