טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentBarzelay Ofir
SubjectDouble Sided Comb Drive with Latching Stator to Minimize
Activating Voltage
DepartmentDepartment of Mechanical Engineering
Supervisor Professor David Elata


Abstract

The goal of this research is to propose a different approach to minimize a Comb-Drive's activating voltage. A Comb-Drive is a MicroMechanical actuator that is activated by electrostatic excitation. The actuator is build from one moving mass (rotor) and a second stationary mass (stator), produced on the same plane of the silicon die. Both masses consist of interdigitated teeth. Electric potential between the two masses creates relative motion between them.

The motion of the rotor is accompanied by a non-linear proportion between its movement and the voltage applied to both masses. It is desirable to achieve a motion that is linearly proportional to the driving voltage so that the rotor could be easily controlled.

Actuator instability is defined as a state where the rotor stops shifting in a direction parallel to the teeth and starts shifting in a direction that is perpendicular to the teeth until, finally, the teeth of the rotor adhere to the teeth of the stator. A new graphic presentation of the domains of instability of the system is presented within the framework of the research.

Reducing the activating voltages of the Comb-Drive, while preserving the linearity of the movement as well as presenting the desirable domain of stability, is enabled by reducing the distance between the teeth of the rotor and the teeth of the stator. The research proposes a new approach for minimizing the distance between the teeth while overcoming limitations of fabrication.

An innovative and comprehensive design of a Comb-Drive which is driven by relatively low voltages, is presented. The actuator’s design is based on applying the results of the research.