In this paper, a dynamic model for an artificial finger driven by Shape Memory Alloy (SMA) wires is presented. Due to their high energy density, these alloys permit the realization of highly compact actuation solutions with potential applications in many areas of robotics, ranging from industrial to biomedical ones. Despite many advantages, SMAs exhibit a highly nonlinear and hysteretic behavior which complicates system design, modeling, and control. In case SMA wires are used to activate complex robotic systems, the further kinematic nonlinearities and contact problems make the modeling significantly more challenging. In this paper, we present a finite element model for a finger prototype actuated by a bundle of SMA wires. The commercially available software COMSOL is used to couple the finger structure with the SMA material, described via the Müller-Achenbach-Seelecke model. By means of several experiments, it is demonstrated how the model reproduces the finger response for different control inputs and actuator geometries.

Date Published: 29 March 2019
PDF: 10 pages
Proc. SPIE 10968, Behavior and Mechanics of Multifunctional Materials XIII, 109680F (29 March 2019); doi: 10.1117/12.2513919

Published in SPIE Proceedings Vol. 10968:
Behavior and Mechanics of Multifunctional Materials XIII
Hani E. Naguib, Editor(s)