Output feedback preview control for polytopic uncertain discrete-time systems with time-varying delay

This paper considers the preview tracking control problem of polytopic uncertain discrete-time systems with a time-varying delay subject to a previewable reference signal. First, a model transformation is employed and a discrete-time system with a time-invariant delay and an external disturbance is obtained. The difference operator method can be extended to derive an augmented error system that includes future information on the reference signal. Then, a previewable reference signal is fully utilized through reformulation of the output equation while considering the output feedback. Based on the small gain theorem, a static output feedback controller with preview actions is designed such that the output can asymptotically track the reference signal. Finally, numerical simulation examples also illustrate the superiority of the desired preview controller for the uncertain system in the paper.