A design of nonlinear model following control system based on modifying nonlinearity with genetic algorithms

A design method for nonlinear model following control systems which guaranteed bounded internal states was proposed by Okubo for a family of plants with separable linear and nonlinear parts, but the requirement for positive real (PR) and inner product conditions for the nonlinear part limits the application of this method. This paper presents a new approach to Okubo's method by extending the state feedback control for linear systems to nonlinear systems, and relaxes greatly the requirement of PR and inner product conditions for the nonlinear part. Using the nonlinear state feedback control, many plants which do not satisfy the inner product condition superficially can be modified to satisfy the inner product condition, and thus can be dealt with by Okubo's method. This paper presents the related proofs and simulations.