LFT-based Stability Analysis of GEneric Guided Missile

Abstract

We present an example of how LFT-based stability analysis can be applied to a nonlinear missile model. The major point is the generation of suitable linear parametric descriptions of the nonlinear model, which allow for accurate and efficient analysis. The basis is a set of linearized state-space systems, which approximate the local behavior of the nonlinear plant. This set is approximated by a linear parametric model employing multivariable polynomial fitting techniques in combination with global optimization. The objective of the optimization is to find linear parametric models that allow the generation of least order linear fractional representations (LFR), which accurately approximate the original nonlinear missile model. Finally, with these LFRs of the missile model a stability analysis is conducted based on the structured singular value.