With the proliferation of unmanned aircraft designed for national security and commercial purposes, opportunities exist to create high-fidelity aerodynamic models with flight test techniques developed specifically for remotely piloted aircraft. Then, highly maneuverable unmanned aircraft can be employed to their greatest potential in a safe manner using advanced control laws. In this dissertation, novel techniques are used to identify nonlinear, coupled, aerodynamic models for fixed-wing, unmanned aircraft from flight test data alone. Included are quasi-steady and unsteady nominal flight models, aero-propulsive models, and spinning flight models. A novel flight test technique for unmanned aircraft, excitation with remote uncorrelated pilot inputs, is developed for use in nominal and nonlinear flight regimes. Orthogonal phase-optimized multisine excitation signals are also used as inputs while collecting gliding, aero-propulsive, and spinning flight data. A novel vector decomposition of explanatory variables leads to an elegant model structure for stall spin flight data analysis and spin aerodynamic modeling. Results for each model developed show good agreement between model predictions and validation flight data. Two novel applications of aerodynamic modeling are discussed including energy-based nonlinear directional control and a spin flight path control law for use as a flight termination system. Experimental and simulation results from these applications demonstrate the utility of high-fidelity models developed from flight data. / Doctor of Philosophy / This dissertation presents flight test experiments conducted using a small remotely controlled airplane to determine mathematical equations and parameter values, called models, to describe the airplane's motion. Then, the models are applied to control the path of the airplane. The process to develop the models and predict an airplane's motion using flight data is described. New techniques are presented for data collection and analysis for unusual flight conditions, including a spinning descent. Results show the techniques can predict the airplane's motion very well. Two experiments are presented demonstrating new applications and the usefulness of the mathematical models.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/110964 |
| Date | 28 June 2022 |
| Creators | Gresham, James Louis |
| Contributors | Aerospace and Ocean Engineering, Woolsey, Craig A., Cotting, Malcolm Christopher, Psiaki, Mark L., Patil, Mayuresh J. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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