Experimental characterization of components for active soft orthotics

In this paper, we present the characterization of soft pneumatic actuators currently under development for active soft orthotics. The actuators are tested statically and dynamically to characterize force and displacement properties needed for use in system design. They are shown to demonstrate remarkably repeatable performance, and very predictable behavior as actuator size (initial length) is varied to adjust total actuation. The results of the characterization are then used to inform design rules for selecting the size and number of actuators for a soft leg orthotic that can produce the force/moment/velocity properties required for a target wearer. The device was tested on a silicone model with inner frame and articulated ankle. Additionally, a portable pneumatic system was developed and characterized, that can actuate the pneumatic actuator over 800 times before refilling the gas supply.