Development of a shape memory alloy actuated biomimetic vehicle

Abstract

The development of a biomimetic active hydrofoil that utilizes shapememory alloy (SMA) actuator technology is presented. This work is the firststage prototype of a vehicle that will consist of many actuated body segments.The current work describes the design, modeling and testing of asingle-segment demonstration SMA actuated hydrofoil. The SMA actuationelements are two sets of thin wires on either side of an elastomeric componentthat joins together the leading and trailing edges of the hydrofoil.Controlled heating and cooling of the two wire sets generates bi-directionalbending of the elastomer, which in turn deflects the trailing edge of thehydrofoil. In this paper the design of the hydrofoil and the experimentaltests preformed thereon are explained. A detailed account of SMA actuatorpreparation (training) and material characterization is given. Finite-elementmethod (FEM) modeling of hydrofoil response to electrical heating of the SMAactuators is carried out using a thermomechanical constitutive model for theSMA with input from the material characterization. The modeling predictionsare finally compared with experimental measurements of the trailing edgedeflection and the SMA actuator temperature.