Intermittent output tracking for linear single-input single-output non-minimum-phase systems

We propose an intermittent output-tracking controller for linear single-input single-output non-minimum-phase systems. For continuous-time non-minimum-phase systems, it is not possible to design tracking controllers that allow the output to asymptotically track an arbitrary reference trajectory. In view of this limitation, we design a controller that takes the output tracking error to zero at regular intervals of time. The proposed controller is designed in continuous time and is therefore different from output tracking controllers designed for discrete-time systems. The proposed control design is composed of three stages; finding a “discrete equivalent” minimum-phase system, designing tracking control for the discrete equivalent system, and finally deriving the switched control input for the non-minimum-phase plant. The reference trajectory can be arbitrary but a finite preview of the trajectory is needed. Numerical simulations are presented to show intermittent output tracking while ensuring internal stability of the closed-loop system.