Design of a discrete-time ASPR based adaptive output feedback control system with a feedforward input

This paper presents a discrete-time adaptive output feedback control system design scheme based on the almost strictly positive real (ASPR) of controlled systems with a feedforward input. The reference signal is used to calculate the feedforward input. It is well-known that a stable adaptive output feedback control system can be designed based on ASPR conditions. However, most realistic systems do not satisfy ASPR conditions. One of alleviation ways is to use various forms of parallel feedforward compensators (PFC) which can configure the ASPR conditions. The problem is output of ASPR augmented system remains output of the original plant. In this paper, an output feedback control system design scheme with feedforward input is proposed in discrete-time. The proposed scheme eliminates the output error and controller structure is much simpler.