Output-feedback adaptive control of electrostatic microactuators

Adaptive control is presented for a class of electrostatic micro-actuators with bidirectional drive. The objective is to track a reference trajectory within the air gap without knowledge of the plant parameters. Motivated by practical difficulties in measuring velocity of the moving plate, an output feedback scheme is developed. After transforming the plant into the parametric output feedback form, adaptive observer back-stepping is employed to achieve asymptotic output tracking. To prevent contact of the movable plate and the electrodes, asymmetric barrier functions are employed in Lyapunov synthesis. All closed loop signals are ensured to be bounded. A simulation study demonstrates the effectiveness of the proposed control.