Biomimetic fish actuated by shape memory alloy

This paper details a design process for the production of the mechanical mechanisms of a biomimetic fish propelled using shape memory alloy actuated pectoral and caudal fins. Three main mechanisms contribute to the biomimicry: pectoral fins, a tail fin, and a ballasting system. The pectoral fin consists of a five fin ray array, which mimics the rowing motion of a biological Koi fish. The tail is comprised of three 3-D printed plastic pieces linked together using springs pulleys and SMA wire, providing flexibility, strength, and biomimetic movement. The ballast allows the fish to change pitch angle allowing us to dive or swim to the surface, ideal for biomimicry. Together and precisely timed, these three components give extremely similar range of motion as biological Koi.