MEMS exural hinge and com- pliant mechanism for electromechan- ical microgrippers

Abstract

Microrobots are used nowadays in several fields of application for many different functions. Unfortunately, their manufacture involves some difficulties as the micrometer scale is out of reach of the traditional machining tools. Consequently, lithographic and etching processes are adopted to achieve high aspect ratios and awless fabrication of the smallest features. The Microrobots under discussion consist in two different kinds of Microgrippers. One has an electrostatic actuation due to two MEMS comb drives that provide the attraction needed to bend a hinge. The other has a different geometry, including two rings connected to metal wires. Forces applied to them result in the bending of 8 hinges that provide the opening and closing motion of the Microgripper. The size of the objects that can be grabbed spreads from 5 m up to 170 m, as in the largest embodiment. The main innovation introduced by the designs presented is a circular hinge, whose thickness ranges from 5 to 18 m. Through its elastic bending it causes the circular motion of the structure. Many aspects make this kind of hinge ideal for MEMS: small size, sole-component, reliability in peculiar environments, lack of friction and wear etc. . . Ideal fields of application are high-precision pick-and-place operations, sample preparation, microassembly, micro-object sorting in both high and low pressure environment, as well as vacuum.