Numeric LFT generation for robust aircraft flutter analysis

In this paper we used the linear fractional representation (LFR) toolbox for the numeric generation of an LFT model. The LFT model was used for structural aircraft analysis in order to determine the onset of flutter. The equation of motion for structural aircraft response is first parametrised in terms of Mach number to obtain matched flutter solutions. From this parametrisation, LFT models for flutter analysis were analytically and numerically generated. The flutter analysis results of the LFT models is compared with flight test results. Finally, an LFT model is generated with perturbations in Mach number, mass, damping and stiffness for robust flutter analysis. The results from this analysis are compared with flight test data and correlate better than unperturbed nominal model analysis.