Aeroelastic Modeling and Adaptive Control of GTM

Abstract

This paper involves modeling and adaptive control of the Generic Transport Model (GTM), which is a notional twin-engine transport aircraft introduced by the NASA Langley Research Center. The aircraft components, namely fuselage, wing, and horizontal and vertical stabilizers are modeled as hollow beams with constant thicknesses. The mass and stiffness distributions of the components are approximated using crosssectional properties, such as geometric center, cross-sectional area, area moments of inertia etc., at some finite number of stations on the respective components. Each beam is assumed to have one bending and one torsional displacements. The aerodynamic forces and moments are generated using a quasi-steady theory. The equations of motion are derived using Lagrange’s Equations in quasi-coordinates. The partial differential equations are discretized by means of the Galerkin method. The resulting equations are a set of nonlinear ordinary differential equations of relatively high order. An optimal control modification adaptive law produces is used to control the longitudinal dynamics of the aircraft under uncertainties.