Unknown Input Observer Design for Linear Discrete Time-delay Systems

This paper is concerned with the unknown input observer design for linear time-delay systems. Based on separating state estimation error from unknown inputs that maybe acting on the system, a different approach by using straightforward matrix equations is provided. Furthermore,necessary and sufficient conditions for the existence of suchobservers are well formulated. The developments are simple and direct compared to other approaches, so it is morepractical. To illustrate the feasibility and capability of the proposed solution, two 3-rd order numerical examples arepresented.