Aerodynamics stability derivatives identification of a sea skimming missile

FERNANDO ANTONIO ALMEIDA COELHO¹; Elder Moreira Hemerly²

¹ Marinha do Brasil; ² Instituto Tecnológico de Aeronáutica

doi:10.20906/CPS/COB-2015-2000

Resumo

The aerodynamics parameters identification of a missile is a necessary issue for the adequate project of their control system. To this end, typically extensive testing in wind tunnels are required, that are not always readily available, in addition to the demand of time and financial resources. Two alternatives arise to overcome these difficulties: i) the so-called engineering methods, in which there are semi-empirics formulas that allow estimating the derivatives of aerodynamic stability with up to 20% errors, according to the literature; and ii) the methods of CFD (Computational Fluid Dynamics), that require specific knowledge and a good deal of intuition to ensure appropriate convergence of the estimates. Therefore, the uncertainties present in such alternatives require the use of a robust controller, which generally are conservative from the point of view of performance. As an alternative to the model refinement, this study investigates the possibility of identifying the longitudinal dynamics of a sea skimming missile, when maneuvers are restricted to its normal flight profile, which could not be persistently exciting to identify the parameters. Simulation results using Simulink and the X-Plane flight simulator allowed the model refinement and their identification only with simple maneuver of decline in altitude. Open loop and closed loop configurations, as well as various combinations of input and output signals were examined and the reference altitude as input, and the pitch angle, angular velocity and altitude demonstrated to be efficient to the identification.

Palavras-chave: parametric identification; aerodynamics derivatives estimation; missile flight dynamics