Development and Application of Silicone Outer Shell-Type Pneumatic Soft Actuators

Abstract

Pneumatic soft actuators exhibit both passive flexibility from the casing and active flexibility from pressurizing and depressurizing. These actuators are expected to be human-friendly and are often used in nursing and medical situations because they allow access to soft systems through control of the internal air pressure. The current design of pneumatic soft actuators has two technical points of interest: the control method for the drive direction and the operating pressure level. An actuator that addresses these points is required. In this study, a pneumatic soft actuator with a silicone rubber casing – called a sponge core soft rubber actuator (SCSRA) – is developed to solve these problems. SCSRAs can perform various functions by changing the bonding state of the silicon film. Thus, a large stroke can be achieved in a low-pressure area of ≤ 30 Pa, and the driving system can be controlled by peeling off and bonding the silicon film. We clarified the expansion and stiffness characteristics of the “bonded SCSRA” and “peeled SCSRA” when unpressurized and pressurized and measured the grip strength when walking in shoes with protrusions on the insole and single-tooth sandals with protrusions on the sole as example applications of the sensing ability.