Bio-inspired morphing caudal fin using shape memory alloy composites for a fish-like robot: Design, fabrication and analysis

In this paper, we present the design and fabrication of a bio-inspired caudal fin actuator for propulsion and maneuvering purposes in a fish-like robot. Shape memory alloy (SMA) composite actuator is customized to provide the necessary work out for the caudal fin. The pocket holes guide, electrical wiring and attachment pads for SMA actuators are all embedded in a single layer of cellulose acetate film, sandwiched between two layers of silicone rubber. Instead of using joints, four SMAs are fixed along the soft structure of the caudal fin and bend this to a certain mode shape. The caudal fin actuator was inspired by Largemouth Bass, which uses sub-carangiform mode swimming and the caudal fin during steady swimming and maneuvering.