Design and fabrication of a shape-morphing soft pneumatic actuator: Soft robotic pad

Silicone-based soft pneumatic actuator (SPA) is one of the key interests in soft robotic research. Currently, most of the SPAs bear a similar one-dimensional rod-like shape, regardless of their design and fabrication. There are few prototypes of SPAs with two-dimensional initial shapes, however, they are basically the linear combination of several one-dimensional SPAs. This paper presents a new class of silicone-based SPA named soft robotic pad (SRP). The SRP is shaped into a soft pad with a single flat air chamber and can generate different kinds of motions according to the internal constraint matrix within the SRP. In this paper, the design and fabrication of our SRPs are elaborated in detail, followed by the preliminary characterization of the different SRP prototypes. Although the current design is not optimized, our SRP prototypes prove the feasibility of the design and fabrication of a 2D shape-morphing SPA. With subsequent optimization, the SRP can work robustly in various real-world applications as strong flat artificial muscles for human joint rehabilitation, or as fins in marine robots.