A NOVEL DESIGN OF FLEXURE BASED, SHAPE MEMORY ALLOY ACTUATED MICROGRIPPER

In this paper, a novel design of a simple, compactly structured, and easy to fabricate microgripper is presented. Stainless steel (St 304) is used as a structural material of the microgripper whereas Shape memory alloy (Ni-Ti) wires are used as actuators. Novel design of microgripper device is presented where two shape memory alloy actuators are used; the first actuator is used to close the gripper jaw whereas the second actuator is used to increasing the opening stroke. The linear and small change in the length of the shape memory alloy (SMA) wire turns into large jaw displacement through flexure hinges (complaint mechanism). In order to develop a microgripper with maximum gripping stroke (jaw displacement) corresponding to minimum stress on flexure hinges, the finite element (FE) analysis using Comsol Multiphysics5.2a software is used to optimize the structural design of the proposed microgripper. Also, stress and displacement finite element analysis are presented for the optimized design of the microgripper. Finally, short comparison between the new design and the previous ones shows better results in terms of increasing the gripper stroke, reducing the stresses on the gripper joints, and conducting new mechanism.