Wiener System Identification with Four-Segment and Analytically Invertible Nonlinearity Model

This paper focuses on modeling and parameter identification of Wiener systems with the ultimate aim of compensating for the nonlinearity in those systems. Four-segment polynomial approximations are investigated for the nonlinear part of the Wiener systems and are shown to perform better than global and two-segment approximations. A special type of polynomial expression is also proposed that makes the analytical inverse of the nonlinearity possible. The idea behind finding inverse of the nonlinearity is to compensate for the nonlinearity introduced into the closed loop systems because of nonlinear sensors.