Development of a shape-memory-alloy micromanipulator based on integrated bimorph microactuators

Abstract

This paper reports a novel structure of a shape-memory-alloy (SMA) micromanipulator with gripping mechanism. A featured integration of multiple SMA bimorph microactuators has been utilized to form a micromanipulator with three degrees of freedom. The design consists of two links (SMA sheets) and a gripper at the end of the second joint. The overall dimensions of the micromanipulator are 33mm×9mm×3mm. The displacement of each actuator is controlled by a heating circuit that generates a pulse-width modulation signal. Theoretical modeling of SMA actuators is studied and verified with simulation. The SMA micromanipulator is able to move in the x- and y-axis by 7.1mm and 5.2mm, respectively, resulting in a maximum displacement of 8.9mm. The micro-gripper has a maximum opening gap between its fingers of 1.15mm. The micromanipulator has a temporal response of 7.5s and 9s for its x- and y-axis. The maximum actuation force generated by the x- and y-axis was around 100mN and 130mN, respectively. The developed micromanipulator has been successfully used to move a small object.