Time-delayed Feedback Control Of The Aeroelastic System

Active flutter suppression is one of the mainstream methods about flutter suppression for aircraft wing. However, the traditional feedback control models don't include time delay, but time delay exists objectively in systems, they will reduce system performance, even make the closed-loop system unstable. Therefore, the time delay stability problem in the flutter supperssion is a brandnew field of aeroelasticity research and need to be further studied. This article takes two-dimensional airfoil and high-aspect-ratio wing as research objects, analysis the stability of controlled aeroelastic system with single time delay and multiple time delays, then design the Corresponding Control Law for flutter suppression.First of all, quasi-steady aerodynamic force model is used, and analysis the complete delay stability for the single degree of freedom aeroelastic system by the generalized Sturm criterion, the delay-independent stable region in the parameter space is obtained. Then discuss the influence of time delay for the system stability.Second, the stability of two-dimensional airfoil with single and double time delays is analysised. The stability of the system is investigated by the quadratic eigenproblem, which is utilized to obtain the double time delays curves of the controlled aeroelastic system.Third, the panel arbitrary aerodynamic model is used to set the aeroelastic equation of two-dimensional airfoil with control plane, on the basis of the optimal discrete-time control method, design the optimal discrete-time control law for the aeroelastic system with time delay. Numerical simulations demonstrated the effect of control law.Last, on the basis of finite element method, structural dynamical model of high-aspect-ratio wing with multiple control effectors is obtained. Unsteady aerodynamic model is obtioned by dipole network method, the minimal state approximation method is used to obtion the aeroelastic equation of the system.The aerodynamic distribution law is calculated.The time delay in the controlled system is approximated by second-order pade. On the basis of H∞control method, the control law which is used to Inhibit Flutter is designed for time delay.