Time-Delay Control of Subcritical Flutter in Two-Degree-of-Freedom Aeroelastic System
Subcritical flutter caused by aerodynamic or structural nonlinear factors causes limit cycle os-cillation in aircraft below the linear flutter critical velocity. This phenomenon leads to deteriorations in the vibration environment of airborne equipment,degradation of flight control performance and other problems,posing a hidden danger to safe flight within the flight envelope. In this paper,a subcritical flutter time-delay feedback controller based on pitching velocity signal is designed for a 2-DOF wing sec-tion with nonlinear stiffness in pitch degree of freedom. At first,a nonlinear aeroelastic mathematical model of a 2-DOF wing section is established by using Lagrange principle. Then,the method of multiple scales is used to derive the analytical solution of the closed-loop control system with time-delay pitching velocity feedback. Subsequently,the stability boundary of the flutter system is determined through sta-bility switching theory,providing the parameter range for the subcritical flutter delay controller. Final-ly,the effectiveness of this subcritical flutter time-delay feedback controller is verified through closed-loop numerical simulations of nonlinear aeroelastic systems under various wind speeds. The simulation results demonstrate that an aeroelastic time-delay feedback controller based on pitching velocity signal can convert subcritical flutter into beneficial supercritical flutter and significantly reducing limit cycle am-plitudes.
wing fluttermethod of multiple scalesnonlineartime-delay feedback control
万方数据
维普
