Functional Observers for Descriptor Systems With Unknown Inputs

This paper addresses the problem of estimating a functional vector for a class of linear time-invariant descriptor systems with unknown inputs. The unknown inputs are considered in both the system dynamics and measurement equations. The proposed observer has an order less than or equal to the dimension of the functional vector to be estimated. The existence of functional ODE observers is proved under simple rank conditions on the system coefficient matrices. A few numerical examples are included to illustrate the proposed theory and designed algorithm.