An integrated gain scheduled control design for an Electrostatic micro-Actuator with aerodynamic effects

In this article an integrated approach regarding the modeling and control design aspects of an electrostatic microactuator (EmA) with aerodynamic effects is presented. The modeling analysis of the squeezed film damping effect is investigated in the case of 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 damping coefficient that is caused because of the thin film of air, is approximated by a frequency independent nonlinear static term. Under this assumption, 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 its plates. Simulation results investigate the efficacy of the suggested modeling and control techniques.