Adaptive Control and Rejection of Persistent Disturbances

In this paper we explore the Direct Model Reference Adaptive Control in [1]-[2] for largescale systems in both continuous and discrete time. The stability results depend upon Strict Positive Realness conditions that have some serious differences in continuous vs. discrete time. We will see that this involves the presence or absence of a linear feed-through or D term. These results are essential for adaptive disturbance cancellation, as has been shown in [3]-[4]. Applications to Aerospace Structures have been shown in [5]-[6]. For the non-adaptive model-tracking control design, we are given a plant model