Modeling and Gain Scheduling Design for an Electrostatic Micro-Actuator with Squeezed Film Damping Effects

E-ISSN： 1876-4037|1|3|234-241

ISSN： 1876-4029

Source： Micro and Nanosystems, Vol.1, Iss.3, 2009-11, pp. : 234-241

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Abstract

In the present article the modeling approach and the control design aspects of an electrostatic microactuator (EmA) under the effect of squeezed film damping are presented. The model of the system accounts for an EmA composed by a set of two plates. The bottom plate is clamped to the ground, while the moving plate is driven by an electrically induced force which is opposed by the force exerted by a spring element. The nonlinear model of the EmA is linearized at various operating points, and the feedforward compensator provides the nominal voltage. Subsequently a gain scheduled H∞ controller is used to tune the controller-parameters depending on the EmA's operating conditions. The controller is designed at various operating points based on the distance between the two plates. The controller's parameters are tuned in an optimal manner and are computed via the use of the Linear Matrix Inequalities. Special attention has been paid in order to examine the properties of the EmA regarding the bifurcations points. Finally, numerous simulation cases are presented in order to prove the efficacy of the presented controller.