An Iterative Approach for Selecting Poles on Complex Frequency Localizing Basis Function-Based Models

Abstract

Modeling dynamic systems from frequency-domain data is a relevant issue for system analysis in many fields of engineering. Many techniques to approach such problems are based on models built by using a series of rational functions with fixed structure. As far as rational basis function models are concerned, the problem of selecting the function’s poles or dynamics is an issue and the Sanathanan–Koerner (SK) iterations represent a successful approach that can be applied to solve it. Frequency localizing basis function (FLBF) models are a rational function which can be used in such a context. However FLBF, as originally proposed, are not suitable for application with SK-iterations because they have not been designed to incorporate complex poles. To overcome this issue and to make the application of SK-iterations possible, this paper proposes a new set of basis functions that are based on the FLBF. In this paper, they will be referred to as complex frequency localizing basis functions. This new set of basis functions preserves the FLBF behavior but real and complex poles can be incorporated in the model and so it allows the use of SK-iterations. The proposed model is validated through simulation.