Full Envelope Nonlinear Parameter-Varying Model Approach for Atmospheric Flight Dynamics

Abstract

This paper presents a nonlinear parameter-varying modeling approach to duplicate the aircraft dynamic behavior while moving from one flight region to another. This approach starts by generating a local two-term truncatedVolterra series, which is enough to capture the quadratic andbilinear nonlinearities, at different operating conditions over the flight envelope. The variation of these series’ coefficient matrices are then sought through different interpolation techniques. A nonlinear F-16 longitudinal model was used to assess the proposed approach. The improvement in the accuracy to predict, understand, and analyze the nonlinear aircraft behavior over the previous linear parameter-varying approach, which effectively ignored the second-order stability and control derivatives, is demonstrated through many numerical test cases.