Field analysis for the electrostatic eccentric drive micromotor (“Wobble Motor”)

Abstract

Methods for and results from electrostatic analysis of a new microactuator are presented. The microactuator, the “Wobble Motor”, is driven by electrostatic torque moving a cylindrical rotor in eccentric motion inside a cylindrical stator cavity. Closed-form mathematical solutions of idealized models for the motor are used to examine limiting behavior and to understand several points of principle. A finite element analysis is used to find theoretical torque values that can be used to compare with experiment, and to guide further development. It is found that the geometric parameters of the motor are related to the electrostatic torque in a rather complex way; the effect on performance of changing one parameter can depend sensitively on the values of the other parameters. Modelling results show that with parameter values that should be achieved with improved fabrication procedures, very large increases in torque should be possible.