FLUTTER SENSITIVITY ANALYSIS USING RESIDUALIZATION FOR ACTIVELY CONTROLLED FLIGHT VEHICLES

Analytical expressions for the derivatives of structural dynamics and control design criteria, with respect to structural and control design variables are extended to deal with residualized aeroservoelastic mod els. The mathematical model considered is a first-order time domain fe edback system subject to model size reduction by means of dynamic resi dualization. The structure is represented by a number of structural vi bration modes and the aerodynamics by minimum-state rational approxima tion functions. The MIMO control system couples control surface motion to the response of motion sensors located on the structure. In the op timum design process for aeroservoelastic systems, considerable comput ation time is spent on calculating the derivatives that define the sen sitivity to design changes. The extended formulation and new technique s of this work make their calculation more efficient and further enhan ce multidisciplinary on-line studies. A realistic numerical example of the optimal design of an aeroservoelastic system comprising a carbon- composite wing with four control surfaces is used to assess the perfor mance of this method.