SMA wire actuator modular design framework

Abstract

Shape memory alloy (SMA) wire actuators are quickly becoming technologically ready for a wider range of commercial applications due both to their exceptional actuation performance and to recent advances in the manufacture of drawn SMA wire. Shape memory alloys are complex materials requiring a breadth and depth of knowledge to successfully implement in more demanding industrial applications, knowledge to which most engineers may not have been exposed. This paper proposes a modular design framework to aid engineers at any level of expertise to synthesize and analyze SMA wire actuators. The modularity of the framework allows for changes in design, architecture, and system topology and allows for easy adaptation to the rapid research advances in the knowledge and understanding of the response and robust use of SMA. The layered structure of the framework is detailed; differentiating the design tasks by function: modeling, evaluation, optimization, and design guidance. Each layer is modular within itself, and in particular, the modeling layer allows for a variety of views to suit the expertise of individual designers. A sample design tool built within the framework is presented for the synthesis of actuators composed of multiple straight SMA wires acting against linear loads, accompanied by a physical system demonstration. This example, while basic, demonstrates the general applicability and flexibility of the framework for aiding many types of users in a large variety of SMA wire actuation design problems.