Modeling and simulation of aeroservoelastic control with multiple control surfaces using mu-method

A modeling and simulation approach to predicting the robust stability of a nonlinear aeroservoelastic system via the mu-method is presented. Mathematical models and implementation issues for the multi-input/multi-output (MIMO) aeroservoelastic system simulation developed for a flexible prototypical wing with leading and trailing edge control surfaces are described. The improvements in the aeroservoelastic analysis and the active flutter suppression (AFS) of a flexible wing structure with multiple control surfaces is accomplished using the mu-method with the uncertainty parameters/perturbations associated with unsteady dynamic pressure, variable structural damping and nonlinear structural stiffness. The motivation of this research is to develop an effective and more accurate methodology in aeroservoelastic analysis by improving the current analysis methods so that it can be readily applied to an aeroservoelastic system design with the validation of test data, and to determine the dynamic performance of an aeroservoelastic system which includes time and frequency responses, system modal properties, critical flutter airspeeds and stability margins.; The mu-control law and algorithms for an aeroservoelastic system with leading and trailing edge control surfaces are developed by combining the MIMO analytical aeroservoelastic model with test data by means of the linear fractional transformation (LFT) and a set of norm-bounded operators (perturbations) Delta that describe modeling errors and uncertainties in the mu-framework. The relevant theories of structural dynamics, aerodynamics, and modern feedback control, as well as flutter, frequency response, poles and stability, aeroservoelasticity/structural-coupling, and mu-based analysis applied to derive the mu-control law for the aeroservoelastic control system are examined.; Simulation results are presented for comparisons of the following: (a) the uncontrolled flexible wing, (b) the active flexible wing with a single trailing-edge flap controller (K1) activated, and, (c) the active flexible wing with both the leading and trailing edge flap controllers (K2 and K1) activated. The improved effectiveness in active flutter suppression by using two control surfaces, and the improved accuracy in modeling an aeroservoelastic system with leading and trailing edge control surfaces are demonstrated.