Multiple Attractor Dynamics in Active Flutter Suppression Problem
An active stabilization of flutter instability was investigated using mathematical model for two degree-of freedom aeroelastic airfoil system with trailing and leading edge flaps. A number of control laws based on LQR, linear eigenstructure assignment and nonlinear dynamic inversion methods have been analysed. The open-loop aeroelastic airfoil system following the onset of linear flutter instability exhibits limit cycle oscillations due to nonlinearities in the torsional and/or bending stiffness. The dynamic properties of the closed-loop system were investigated using a systematic search method for all possible equilibrium solutions and the continuation of limit cycles by application of the numerical continuation package MATCONT. A computational analysis revealed that multiple attractors can coexist in the closed-loop system. These multiple attractors include a stabilized equilibrium, transformed open-loop limit cycle oscillations with large amplitude and asymmetrical equilibria or asymmetrical oscillations with small amplitude, induced by feedback control law. The size of region of attraction of a stabilized equilibrium depends on the size of unstable saddle-type limit cycle and may be dramatically reduced due to onset of additional asymmetrical equilibrium solutions. The computational analysis showed that for a global stabilization of flutter instability a designed control law should annihilate or destabilize the open-loop limit cycle and prevent the onset of asymmetrical equilibria.
Citation : Goman, M.G. and Demenkov, M.N. (2009) Multiple Attractor Dynamics in Active Flutter Suppression Problem. Proceedings of The Seventh International Conference on Mathematical Problems in Engineering Aerospace and Sciences, Genoa, June 2008, 950pp.
ISBN : 9781904868705
Research Group : Centre for Engineering Science and Advanced Systems
Peer Reviewed : Yes