Dynamic surface control for constrained electrostatic micro-actuators with uncertain time delays

In this paper, dynamic surface control (DSC) is investigated for a class of electrostatic micro-actuator systems which can be actively driven bidirectionally. In the presence of unmatched uncertain time delays, the proposed controller ensures the system state can track a reference trajectory within the desired air gap without knowledge of the plant parameters. By introducing tangent barrier function, the system state keeps in a desired region to prevent contact between the movable and fixed electrodes, while not violating the constraint during the transient response. Moreover, compared with convention backstepping design, both the design produce and derived tracking controller itself are simplified by the proposed method. In addition, simulation results show that the excellent transient tracking performance can be achieved by the proposed controller.