The Frequency Response Estimation Using Swept-sine Excitation with Observer

Abstract

This paper deals with obtaining the frequency characteristics of a linear system. A new approach for nonparametric system identification based on the use of a state reconstructor and a sinusoidal swept excitation signal is proposed.The designed solution provides frequency characteristic estimation with the ability to accurately measure points with specific phase lag. Otherwise, the quality of the estimate depends on the sweeping ratio, which is changed adaptively with respect to the desired accuracy. Another parameter to be adaptively varied is the amplitude of the excitation signal, thereby keeping the experiment in the linear mode in the permissible neighborhood of the operating point.The algorithm in the form of a function block is implemented in the REXYGEN control system from the Czech SME company REX Controls.