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DINAME 2017
XVII International Symposium on Dynamic Problems of Mechanics
NONLINEAR IDENTIFICATION USING POLYNOMIAL NARMAX MODEL AND A STABILITY ANALYSIS OF AN AEROELASTIC SYSTEM
Submission Author:
Raphaela Carvalho Machado , SP
Co-Authors:
Raphaela Carvalho Machado, Luiz Carlos Góes, Airton Nabarrete, José Manoel Balthazar, David Castillo
Presenter: Raphaela Carvalho Machado
doi://10.26678/ABCM.DINAME2017.DIN17-0215
Abstract
This work describes the nonlinear identification applied to an aeroelastic pitch-plunge system using polynomial NARMAX model and a stability analysis. The apparatus is available and consists of a wing typical section with pitch and plunge degrees of freedom. The rigid wing has one flight control surface and is supported by an elastic structure with low damping. The identification procedure aims to obtain the parameters for the mathematical model incorporating the nonlinearity to the support torsional stiffness as a quadratic polynomial function. The candidate structure to the polynomial NARMAX model is obtained from discretization of the continuous-time state-space model that has been derived from the governing equation of motion of the aeroelastic system considering two degrees of freedom. Theoretical continuous-time model parameters and equation coefficients relationship are presented. The predictions for the theoretical discrete-time model are obtained via the identification procedure using polynomial NARMAX model with data from the simulated model. This simulation is performed considering the aerodynamics promoted by wind tunnel with free stream velocity increased within an established velocity range which includes the flutter phenomenon. In future work, the nonlinear identification using the experimental data acquisition from the experimental apparatus will be performed. The polynomial NARMAX model indicates a polynomial function of fourth order for representing the nonlinear torsional stiffness of the dynamic system. The stability analysis is also discussed in this work and a mapping with nonlinear regions is shown.
Keywords
nonlinear system identification, polynomial NARMAX model, aeroelastic system, stability analysis
