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Nonlinear Adaptive Controller Design For Air-breathing Hypersonic Vehicles

Fiorentini, Lisa
http://rave.ohiolink.edu/etdc/view?acc_num=osu1274986563

Abstract Details

2010, Doctor of Philosophy, Ohio State University, Electrical and Computer Engineering.
This dissertation presents the design of two nonlinear robust controllers for an air-breathing hypersonic vehicle model capable of providing stable tracking of velocity and altitude (or flight-path angle) reference trajectories. To overcome the analytical intractability of a dynamical model derived from first principles, a simplified control-oriented model is used for control design. The control-oriented model retains the most important features of the model from which it was derived, including the non-minimum phase characteristic of the flight-path angle dynamics and strong couplings between the engine and flight dynamics. The first control design considers as control inputs the fuel equivalence ratio and the elevator and canard deflections. A combination of nonlinear sequential loop-closure and adaptive dynamic inversion has been adopted for the design of a dynamic state-feedback controller. An important contribution given by this work is the complete characterization of the internal dynamics of the model has been derived for Lyapunov-based stability analysis of the closed-loop system, which includes the structural dynamics. The results obtained address the issue of stability robustness with respect to both parametric model uncertainty, which naturally arises in adopting reduced-complexity models for control design, and dynamic perturbations due to the flexible dynamics. In the second control design a first step has been taken in extending those results in the case in which only two control inputs are available, namely the fuel equivalence ratio and the elevator deflection. The extension of these results to this new framework is not trivial since several issues arise. First of all, the vehicle dynamics are characterized by exponentially unstable zero-dynamics when longitudinal velocity and flight-path angle are selected as regulated output. This non-minimum phase behavior arises as a consequence of elevator-to-lift coupling. In the previous design the canard was strategically used to adaptively decouple lift from elevator command, thus rendering the system minimum phase. Moreover, the canard input was also employed to enforce the equilibrium at the desired trim condition and to provide a supplementary stabilizing action. As a result, when this control input is not assumed to be available, the fact that the system needs to be augmented with an integrator (to reconstruct the desired equilibrium) and the non-minimum phase behavior have a strong impact on the control design. In these preliminary results the flexible effects are not taken into account in the stability analysis but are considered as a perturbation and included in the simulation model. The approach considered utilizes a combination of adaptive and robust design methods based on both classical and recently developed nonlinear design tools. As a result, the issue of robustness with respect to parameter uncertainties is addressed also in this control design. Simulation results on the full nonlinear model show the effectiveness of both controllers.
Andrea Serrani (Advisor)
Stephen Yurkovich (Committee Member)
Kevin Passino (Committee Member)
Scott Gaudi (Committee Member)
100 p.
Electrical Engineering
nonlinear control; adaptive control; aircraft control; hypersonic vehicles

Recommended Citations

Citations

  • Fiorentini, L. (2010). Nonlinear Adaptive Controller Design For Air-breathing Hypersonic Vehicles [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274986563

    APA Style (7th edition)

  • Fiorentini, Lisa. Nonlinear Adaptive Controller Design For Air-breathing Hypersonic Vehicles. 2010. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1274986563.

    MLA Style (8th edition)

  • Fiorentini, Lisa. "Nonlinear Adaptive Controller Design For Air-breathing Hypersonic Vehicles." Doctoral dissertation, Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274986563

    Chicago Manual of Style (17th edition)

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This open access ETD is published by The Ohio State University and OhioLINK.