A Two Degree of Freedom Gripper Actuated by SMA with Flexure Hinges

Abstract A gripper prototype was designed and built. It is made by a rigid structure articulated by compliant hinges. Its kinematics consists of both parallel and angular finger motion. The movements were designed to be independent from each other and auto‐adaptive as well. The motions were driven by Ni‐Ti shape memory alloy (SMA) wires. The recovery position is achieved by the elastic force exerted by the flexure hinges in the case of parallel motion and by an axial spring in the case of angular motion. Both the actuators and the hinges were experimentally characterized by suitable test rigs. The gripper prototype was tested and it showed to be able to reach the design performances. © 2003 Wiley Periodicals, Inc.