Artificial Pnumatic Muscles

Artificial Pneumatic Muscles (McKibben Muscles) are lightweight actuators which are working by pressurizes air. The use of these artificial muscles in AFO is because of their similar behavior to muscles in providing contractile or extensional actuation. However because of their need to pressurized air they are not suitable for outdoor activities but can be used in the lab for rehabilitation and muscle activation.
As shown in left figure, one pneumatic actuator provides plantar flexion torque and the second one provides dorsiflexion torque. A control algorithm adjusts air pressure in each actuator independently.
In this AAFO a combination of foot switch control and myoelectric control is used. The main signal in the myoelectric control is the electromyogram which is a small electric signals produced by the muscles during activations.

BME 240, Spring 2008 Leyla Esfandiari