RIPPLE-FREE TRACKING PROBLEM

In the deadbeat control of discrete plants originating from continuous ones, it is important to have exact tracking, not only at the sampling instants, but also in between the instants. This paper investigates such a problem in the general case of a reference signal that can vary within a pre-specified class. The design procedure proposed is based on a polynomial algebra approach. An internally stable closed-loop system is derived by means of an algorithm, where the transfer function of the controller originates from the solution of a set of linear equations. Algebraic conditions determine the minimum time control scheme. Numerical examples are reported.