Active Spanwise Lift Control: A Distributed Parameter Approach

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dc.contributor.advisorHubbard, James Een_US
dc.contributor.authorDias, Joaquimen_US
dc.contributor.departmentAerospace Engineeringen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2020-02-01T06:36:27Z
dc.date.available2020-02-01T06:36:27Z
dc.date.issued2019en_US
dc.description.abstractStructural load alleviation has been a very active research topic since the 1950s for many reasons. By mitigating the effect of gusts on the wing, the maximum loads can be effectively reduced. This capability would lead to substantial benefits, such as reduced structural weight, better fuel burn performance, and improved passenger ride comfort. Instead of controlling the structural response, however, it can be argued that the aerodynamic behavior of the wing should be primarily controlled. Since the gust loads are caused by disturbances in the lift distribution, it is possible to mitigate the gust loads by controlling the shape of the lift distribution profile along the span. In contrast to previous approaches, this research builds on concepts from Distributed Parameter Systems (DPS), which is indeed the case of aerodynamic surfaces. The unsteady aerodynamic behavior of the 3D flow around a wing is modeled using two approaches: the Unsteady Lifting-Line Theory (ULLT) and the Unsteady Vortex-Lattice Method (UVLM). Then, modal identification techniques are used to identify spanwise aerodynamic mode shapes in terms of local lift coefficient along the span. These shapes provide an optimal basis for model order reduction and also for spatial control. The lift distribution is decomposed as a linear superposition of these shapes, with each weighted by a shape coefficient. By controlling a set of shape coefficients, the overall lift profile can be effectively controlled. In this work, the shape control problem is addressed using a Linear Quadratic Tracker to dynamically follow any desired reference lift profile. The gust alleviation problem is investigated using a similar controller with a special observer, able to decouple the state estimation from the gust input.en_US
dc.identifierhttps://doi.org/10.13016/ahx3-m40g
dc.identifier.urihttp://hdl.handle.net/1903/25409
dc.language.isoenen_US
dc.subject.pqcontrolledAerospace engineeringen_US
dc.subject.pquncontrolledAerodynamic modesen_US
dc.subject.pquncontrolledLift distribution controlen_US
dc.subject.pquncontrolledModal decompositionen_US
dc.subject.pquncontrolledNon-self-adjoint systemsen_US
dc.subject.pquncontrolledShape controlen_US
dc.subject.pquncontrolledSpatial controlen_US
dc.titleActive Spanwise Lift Control: A Distributed Parameter Approachen_US
dc.typeDissertationen_US

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