Flutter sensitivity analysis using residualization for actively controlled flight vehicles

Abstract

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 models. The mathematical model considered is a first-order time domain feedback system subject to model size reduction by means of dynamic residualization. The structure is represented by a number of structural vibration modes and the aerodynamics by minimum-state rational approximation functions. The MIMO control system couples control surface motion to the response of motion sensors located on the structure. In the optimum design process for aeroservoelastic systems, considerable computation time is spent on calculating the derivatives that define the sensitivity to design changes. The extended formulation and new techniques of this work make their calculation more efficient and further enhance 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 performance of this method.