The increased flexibility of wind turbine blades necessitates not only accurate predictions of the aeroelastic effects, but also requires active control techniques to overcome potentially damaging loadings and oscillations. An aeroservoelastic model, capturing the structural response and the unsteady aerodynamics of very large rotors, will be used to demonstrate the potential of closed-loop loa...

The development of several adaptive internal structures concepts is described that are aimed towards enabling adaptive static aeroelastic shape control of an aircraft wing in flight. It is shown how changes in the position, orientation and stiffness of the internal wing structure can be used to change the bending and torsion stiffness properties of a wing, and hence to control the aerodynamic p...

Abstract. In this work an alternative beam finite element for rapid time-domain flutter analysis of wings equipped with trailing edge control surfaces, generally distributed along the span, is presented. The aeroelastic proposed based on Euler-Bernoulli theory, De St. Venant torsion theory and two-dimensional unsteady aerodynamics. developed model attractive preliminary aero-servo-elastic analy...

This paper introduces an adaptive flutter suppression control algorithm which is based on the iterative estimate of the aeroelastic plant and design of the feedback controller. In this algorithm, the dual-Youla parametrization is implemented as an essential part to estimate the open loop aeroelastic model from the closed loop experiment. The advantage of utilizing the dual-Youla parametrization...

In the present paper, the aeroelastic stability of helicopter rotor blade is determined using Aeroelastic Frequency Response Function. The conventional methods of aeroelastic stability usually use an iterative procedure while the present method does not require such approach. Aeroelastic Frequency Response Functions are obtained by inverting dynamic stiffness matrix of the aeroelastic system. S...

Lightweight aircraft design has received a considerable attention in recent years as a means for improving cruise efficiency. Reducing aircraft weight results in lower lift requirements which directly translate into lower drag, hence reduced engine thrust requirements during cruise. The use of lightweight materials such as advanced composite materials has been adopted by airframe manufacturers ...

A very flexible unmanned aerial vehicle has been designed and manufactured at the University of Michigan. The vehicle is named X-HALE, whose flight tests are expected to provide important data of its geometrically nonlinear aeroelastic behavior coupled with the six rigid-body degrees of freedom. As the target of the aeroelastic design, the X-HALE vehicle will present unstable aeroelastic/flight...

The ‘‘stick’’ type aeroelastic model, referred to here as ‘‘aeroelastic balance,’’ has served as an effective tool for investigating wind-induced response of tall buildings and towers in both fundamental research as well as design applications. However, some questions still remain unaddressed in the available literature regarding the efficacy of the aeroelastic balance as a design tool. These c...

This paper presents a distributed parameter optimal control method. The state-space equation of wing bending-torsion aeroelasticity is formulated using aeroelastic differential operators. The optimal control problem is formulated as linear quadratic regulator in a Hilbert inner product space. The solution to the optimal control problem leads to a differential operator Ricatti equation. Using a ...

Two 2-D aeroelastic models are presented here to determine instability boundary (flutter speed) and gust response of a typical section airfoil with degrees of freedom in pitch and plunge directions. To build these 2-D aeroelastic models, two different aerodynamic theories including Indicial Aerodynamic Theory and Vortex Lattice Method (VLM) have been employed. Also, a 3-D aeroelastic framework ...