Modeling and Identification of a Shape Memory Alloy Robotic Finger Actuator

Abstract

In this research work, model and identification for an artificial finger actuated by Shape Memory Alloy (SMA) wires is presented. The high energy density and flexibility of these alloys permits the design of compact actuation solutions with possible applications in robotics fields, ranging from industrial to biomedical ones. On the other hands, the hysteretic and highly nonlinear response of SMAs complicates system design, modeling, and control. As a first step towards the design of accurate position and interaction control algorithms, in this paper we develop a control-oriented model for the SMA actuated finger prototype. The model, based on a coupling between the finger structure with the Miiller-Achenbach-Seelecke model for SMA material, allows to describe the dynamic and hysteretic response of the device in a physics-based fashion. After discussing the model, several experiments are performed tries in order to validate the model for several operating conditions.