Performance Evaluation of a MEMS Compact Electrostatic Microgripper Equipped with Rotary Comb Drives and Curved Flexure Hinges

Microgrippers can be conveniently designed and built as MEMS-Technology based devices for handling and manipulating objects at a microscopic scale. In this work is presented a microgripper equipped with curved flexure hinges. The design is specifically studied to improve its grasping capabilities with respect to those found in literature, while maintaining a small overall footprint of 20 mm
²
, and a well established fabrication procedure (Silicon-On-Insulator technology). The microgripper is electrostatically actuated through five rotary comb-drives made of interdigitated fingers. Finite Element Analysis has been adopted to analyze the system performance when voltage is applied. As main figures of merit, the tip displacement and rotation, the maximum stress sustained by the flexure hinges and the maximum operating voltage (MOV) are investigated. A tip displacement up to $39 \mu \mathrm{m}$ and a tip rotation of about 1° were achieved at 15 V of MOV, better than other electrostatically driven microgrippers presented in literature. Such microgripper enables the manipulation of objects with size ranging from a few microns to tens of microns requiring relatively low voltage, thus suggesting its use in the field of integrated micromanipulation and micro-surgery.