Transfer Function Tracking of a Linear Time-Varying System By Means of Auxiliary Simple Lag Networks

One of the most important problems facing a control engineer today is to find a simple and satisfactory method for determining the transfer function of an unknown time-varying control system. In this paper the transfer function is represented by a gain constant and ratio of two rational polynomials of s, where s is Laplace variable. The gain constant and the coefficients in the polynomials vary in an unknown fashion but rather slowly. A method is developed whereby as many independent signals are developed as the number of unknown coefficients. These signals are used to determine the unknown coefficients in a straightforward manner.