MULTI–PARAMETRIC H∞ CONTROL OF A MICRO ACTUATOR

Abstract

In this article the control problem of a micro-actuator (μ – A is considered. The μ – A is composed of a micro-capacitor, whose one plate is clamped while its other flexible plate's motion is constrained by hinges acting as a combination of springs and dashpots. The distance of the plates is varied by the applied voltage between them. The flexibility of the moving plate coupled to the dynamics of the plate's rigid-body motion results in an unstable, nonlinear system of distributed nature. Utilization of FEM can approximate the μ – A dynamics nonlinear-PDE to a finite nonlinear-ODE. The nonlinearity stems from the plate's rigid-body motion, while all flexibility effects are considered as additive linear-terms. A controller composed of: a) a feedforward term for regulation at selected setpoints, and b) a constrained finite time optimal controller to handle any deviations from the equilibrium is synthesized. Simulation studies are used to investigate the efficacy of the suggested controller.