Offset-Free Control of Time-Delay Linear Discrete Systems Subject to Input and State Constraints: Reference Input Management Approach

In this paper, a novel offset-free control strategy is proposed for delayed discrete-time linear systems with constraint in control input and state. The proposed strategy is based on the reference input management approach and consists of two control loop: inner and supervisory loop control. At first, an augmented delay-free model is introduced and its controllability is investigated. Then, necessary and sufficient conditions for offset-free control of delayed systems are expressed. According to the augmented model and regardless the constraints presence, a suitable tracking controller is designed to form inner loop. The proposed tracking controller is determined in such a way that the resulted closed-loop model to be applicable to compute the so-called maximal output admissible set (MOAS) as the core of reference governor (RG) strategy. Finally, the supervisory loop is formed by reference governor (RG) block to manage the manipulated reference input for guaranteeing the constraint satisfaction. At the end, a numerical example illustrated to show the efficiency of the proposed strategy.