M.Sc Thesis

M.Sc StudentYulzary Shay
SubjectThe Electromechanical Response of a Double-Axis
Electrostatic Comb-Drive Actuator
DepartmentDepartment of Mechanical Engineering
Supervisors PROFESSOR EMERITUS Yoram Halevi
PROF. David Elata
Full Thesis textFull thesis text - English Version


A novel double axis in-plane comb-drive actuator is presented in this work. In contrast to previous designs; which use several single axis comb-drives, the current device uses a single comb-drive to achieve such motion. The device is activated by applying two actuation voltages. By varying these two actuation voltages a two dimensional displacement is achieved, such that the entire range of stable equilibrium displacements can be obtained. This work focuses on the quasi-static response of the device.

The displacements, which are points along the quasi-static equilibrium curves of the device, are analyzed. In addition, the electro-mechanical stability limitation, known as Pull-in, is derived. Several devices were designed and fabricated.

An experimental measurement method and system, which were developed in order to measure the response of these devices, are presented. This experimental system includes image acquisition and an image processing procedure. The image acquisition is synchronized with the driver, which supplies actuation voltages to the device.

The measured response of the devices is presented and compared to theoretical predictions. Overall, the measured results are found to be in a fair agreement with the theoretical predictions, yet some differences are observed. These differences are discussed and explained. A Finite Elements analysis is preformed, in order to evaluate the dominant non-linearity in the device response, which is caused by a Fringing field effect.

Finally, aspects of the measurement system are described. Specifically, accuracy and repeatability of the measurements were characterized.