Parameter Varying Control of an Electrostatic MEMS Actuator

The present paper employs a linear parameter-varying (LPV) control design approach with H_∞ performance specification for set-point tracking of deflection in an electrostatic MEMS actuator. First, we model the system dynamics in an LPV framework, considering the actuation charge as the scheduling parameter. Then, we design an H_∞ parameter-dependant state feedback controller, where its static gain is scheduled based on the LPV parameter. The states of the modeled LPV system are estimated using an LPV observer whose design is addressed in the paper. The simulation results presented in the paper provide asymptotic stability and desired performance against pull-in effect and vibration disturbance. Also the performance of the LPV controller is compared with a fixed H_∞ controller to demonstrate that the LPV controller provides smaller settling time, lower overshoot and hence improved transient and steady-state performance over full range of device operation.