Derivation of system matrices from nonlinear dynamic simulation of jet engines

Abstract

Most multivariable control design methodologies are linear theories and utilize a linearized plant model. Since accuracy of a linearized plant model affects the quality of a control system designed by those methods, a reasonable linearized plant model that adequately simulates the plant must be prepared. This paper describes a derivation method of such a model in the form ofABCD system matrices from nonlinear dynamic simulation. System matrices of a two-spool turbofan engine are derived and compared to the actual engine data. The effect of perturbation size and linearization formula over a linearized model are discussed. A corrected form of the system matrices is introduced to extend the data base to the whole flight envelope.