Robustness Analysis of a Dynamic Vibration Absorber Applied to a Helicopter for the Mitigation of Instabilities.
Diogo Bertolini Profeta de Oliveira1; Leonardo Sanches1; João Flavio Pafume Coelho2; Guilhem Michon2
1 Universidade Federal de Uberlândia, Laboratório de Mecânica de Estruturas José Eduardo Tannus Reis; 2 Université de Toulouse, ICA-ISAE
doi:10.20906/CPS/CILAMCE2015-0334
Resumo
This paper presents a robustness analysis of the use of dynamic vibration absorbers (DVA) for the mitigation of instabilities due to the ground resonance phenomenon in helicopters. The DVA, located in the fuselage, alters the dynamic behavior of the helicopter and, consequently, its stability characteristics when it is on the ground. It has been proven by the authors in earlier works that the DVA helps to reduce the instabilities due to ground resonance. The purpose of this work is to use the lifting procedure in the uncertain linear time period (LTP) model of the system (helicopter+DVA) and transform it into an augmented linear time invariant (LTI) in order to allow the application of μ-analysis tools. The lifted model calculated by the μ-analysis is compared with the Floquet Theory in a parametric configuration for a range of rotor angular rate. The helicopter model has four blades and the parametric uncertainties taken into account are the dynamic characteristics (stiffness and damping) of one blade.
Palavras-chave: Ground Resonance; Floquet's Theory; Vibration Absorbers; Robustness Analysis