Discrete-time 2DOF control design with a generalized predictor for stable and integrating processes with time delay

In this paper, a discrete-time domain two-degree-of-freedom (2DOF) control design based on a generalized delay-free output predictor is proposed for stable and integrating processes with time delay. First, a generalized delay-free output predictor is constructed to obtain the delay-free output prediction, such that the controller design could be focused on the delay-free plant. Then, two 2DOF controllers are analytically designed to realize the set-point tracking and disturbance rejection, respectively, followed by robust stability analysis based on the small gain theory. A significant advantage of the proposed control scheme is that there exists only one adjustable parameter in the prediction filters, or the 2DOF controllers, which could be monotonically tuned to make a trade-off between control performance and robust stability. Two illustrative examples from the literature are given to demonstrate the effectiveness and superiority of the proposed method.