Finite Element Modeling and Simulation of a Robotic Finger Actuated by Ni-Ti Shape Memory Alloy Wires

摘要

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