DESIGN AND ANALYSIS OF A COMPLIANT LINEAR-TO-ROTARY MOTION TRANSDUCTION MECHANISM BY A MEMS COMB-DRIVE ACTUATOR

Abstract

A mechanism to convert linear motion to rotary motion has been studied for application in microelectromechanical systems (MEMs). The means to achieve the linear-to-rotary motion transduction is attributed to a symmetric arrangement of two linear motion inputs. The linear motion is provided by comdrive actuator suspended by symetrical springs system. The translational movement is formed by the electrostatic force that act between the movable comb-drive acting as V_- and the fixed comb-drive working as the V_+. In order to achieve a transduction ratio of the rotation compared to the linear motion, the Genetic Algorithm is used to optimize the design for the Bézier parametric curve. In this investigation, composite materials consisting of a metal layer and a silicon dioxide 〖SiO〗_2 layer above and below the metal layer were used to fabricate the structure. With a break-through in the high tech technology, this rotary motion can be applied for various optical applications like, attenuation, switching and diffraction, etc. Finite element analyses were carried out to predict behaviors of the transduction mechanism. A transduction ratio of nearly 1.2 degree/µm is achieved. To meet the fabrication requirements, the mechanism integrating the control circuit will be designed using Cadence Virtuoso software. Based on the simulation results, the out-of-plane displacement at the rotary stage is very small, proving that the structure does not twist or sag when voltage is applied. In addition, the stress generated in the structure is much smaller than the allowable stress of the material. An experimental system is presented to determine the operability of the device.