Padé-type order reduction of two-dimensional systems

The problem of reducing the order of the transfer function of a given two-dimensional system to a lower order model using Padé-type approximation is considered. Two computational algorithms are proposed. The first is a generalization of the known one-dimensional Padé-type approximation algorithm. The second is a computationally improved version of the first since it involves the parameters of the transfer function of the given system directly, thus circumventing the task of determining the power series expansion coefficients of the given transfer function required in the first algorithm.