Upper-Limb Exoskeleton Robot Design Driven by a Pneumatic Artificial Muscle Actuator

The present study aims the development of an exoskeleton arm for the upper limb using a pneumatic muscle actuator. The pneumatic artificial muscle (PAM) is a soft actuator made of an inflating and flexible membrane protected by a braided sleeve made of polyethylene terephthalate to withstand weights and prevent inner membrane rupture. The inner membrane is fabricated using liquid silicone being cast in defined dimensions by casting. The inner membrane is pressurized by air compressors resulting in the inflation of the membrane. The variable actuation with variable stiffness depends upon the nonlinear characteristics of the flexible membrane and pressures. Different pressure leads to varied actuation aspects, so the lifting capacity variance is noted. A 3/2 solenoid valve with electromyography sensors, which base their control of the intended PAM on the electric signal sensed through human muscle action. A sequence of PAMs provides the exoskeleton arm with one degree of freedom at the elbow and is tested for various weights and actuation ratios. The exoskeleton arm finds use in rehabilitation by combining soft robotics and medical applications with human interaction.