Design, Fabrication, and Experimental Testing of a SMA-Actuated Soft Fin Inspired by a Cownose Ray

This paper presents the design, fabrication, and testing of a soft fin inspired by the cownose ray actuated using shape memory alloys (SMAs). The SMAs are embedded in the silicone rubber, which made the fabrication process particularly challenging but allowed the fin’s movement to mimic the natural movement of ray fins better. The fin was tested, measuring the forces produced at different actuation frequencies and voltages. The generated thrust and the quality of the movement have been compared with an identical fin actuated by servomotors. This work demonstrated the potential of SMA-actuated fins in soft robotic fishes, highlighting significant differences in thrust generation and movement quality compared to those actuated by servomotors.