Partial state estimation: A new design approach

There are three different approaches for functional observer design for Linear Time-Invariant (LTI) systems within the literature. One of the most common methods has been proposed by Aldeen [1] and further developed by others. We found several examples in which the necessary and sufficient conditions for the existence of a functional observer are actually not sufficient for this methodology. This finding motivated us to develop a new methodology for designing functional observers. Our new method provides enough degrees of freedom for the observer design parameter and it improves the weakness within the Aldeen´s method in solving the observer coupled matrix equations. In this paper, we present the reason and an example to show the insufficiency of the former method. Furthermore, we present our new developed methodology. An illustrative algorithm also describes the design procedure step by step. A numerical example and simulation results support our findings and performance of the proposed method.