Model Updating Nonlinear System Identification Toolbox, Phase I

ZONA Technology proposes to develop an enhanced model updating nonlinear system identification (MUNSID) methodology by adopting the flight data with state-of-the-art control oriented techniques. The end product is a flight data enhanced MUNSID/ZAERO toolbox for accurate predictions of flutter and limit cycle oscillation (LCO) instabilities.

The enhancement employs control oriented techniques, namely, model uncertainty, linear fractional transformation framework, mu-analysis and nonlinear operators identification, to adopt the emerging aeroelastic flight-test data. This toolbox augments the current match-point solution approach using the mu-analysis method with identified nonlinear operators. The procedure calls for ZAERO's high-fidelity linear aeroelastic model to be tuned quickly with available aeroelastic/aeroservoelastic, AE/ASE, flight data sets, while block-oriented models are used to highlight the underlying nonlinear structure of the AE/ASE system. This framework is capable of accounting for several nonlinearities including those due to aerodynamics, structures, control/actuator, and/or geometry. The toolbox will be used as the next-generation flutterometer to predict the onset of AE/ASE instabilities. Two case studies, simple and complex dynamic ASE systems, are proposed to validate and verified this advanced control-oriented concept. This enabling technology will be invaluable to the flight test community by extending the current industry modeling tools to include nonlinear operators identified from wind-tunnel/flight-test data.