Structural Design and Realization of Electromechanical Logic Elements Using Shape Memory Alloy Wire Actuator

This paper presents the design, physical modelling and testing of electromechanical logic elements using shape memory alloy (SMA) wire actuated hinged beam switches. Microelectromechanical system logic devices actuated by electrostatic, pneumatic and electrothermal actuation mechanisms are used as alternatives to the conventional logic systems for harsh operating conditions such as ionizing radiations and high temperature. Microoptoelectromechanical system logic device actuated by electrothermal cantilevers can be used in the same applications. Mechanical logic units using linkages and joints in automobiles require an appropriate actuation mechanism. The actuation mechanism used in each case is inherent to typical limitations and design complexity. This work contributes to the evolution of the mechanical logic design architecture to present simplicity to the logic system, involving SMA actuated hinged beam switches. The performance of the SMA hinged beam switch is evaluated by assessing the minimum current required for the actuation of the SMA to reduce the switching delay; also the switching transients during ON and OFF are observed for a static input. The functionality of basic electromechanical logic elements composed using SMA hinged beam switch is verified.