Design and testing of a biomimetic tuna using shape memory alloy induced propulsion

Current unmanned undersea vehicles (UUVs) are almost exclusively propeller driven designs, which must inherently be optimized for a particular speed, sacrificing low speed manoeuvrability for cruising efficiency. Recently, biomimetic approaches to underwater vehicle propulsion have illuminated the exciting possibilities for performance improvements made possible by emulating fish motion. In particular, a number of test vehicles indicate that the carangiform swimming mode employed by highly developed species of fish, such as the Bluefin tuna, offers both a more efficient propulsion mechanism than propellers, in addition to the ability to perform quick manoeuvring. This paper presents the design, construction and testing of a biomimetic tuna that employs shape memory alloy wires to affect shape induced propulsion. Issues related to a smart structures design approach for application in UUVs are presented, including swimming parameters for the vehicle operation.