Applying Eigenstructure Assignment to Inner-Loop Flight Control Laws for a Multibody Aircraft

Alexander Köthe; Robert Luckner

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CEAS EuroGNC 2019

Applying Eigenstructure Assignment to Inner-Loop Flight Control Laws for a Multibody Aircraft

Alexander Köthe	Technische Universität Berlin, Berlin, Germany
Robert Luckner	Technische Universität Berlin, Berlin, Germany

Abstract:
Unmanned aircraft used as High-Altitude Platform System have been studied in research and industry as alternative technologies to satellites. Regarding actual operation and flight performance of such systems, multibody aircraft seem to be a promising aircraft configuration. In terms of flight dynamics, this aircraft strongly differs from classical rigid-body and flexible aircraft, because a strong interference between flight mechanic and formation modes occurs. For unmanned operation in the stratosphere, flight control laws are required. While control theory generally provides a number of approaches, the specific flight physics characteristics can be only partially considered. This paper addresses a flight control law approach based on a physically exact surrogate model rather than conventionally considering the system dynamics only. Hypothetical spring and damping elements at the joints are included into the equations of motion to transfer the configuration of a highly flexible multibody aircraft into one similar to a classical rigid-body aircraft. The differences between both types of aircraft are reflected in the eigenvalues and eigenvectors. Using the eigenstructure assignment, the desired damping and stiffness are established by the inner-loop flight control law. In contrast to other methods, this procedure allows a straightforward control law design for a multibody aircraft based on a physical reference model.

Keywords: Aircraft flight control analysis and design

View PDF CEAS-GNC-2019-027

Alexander Köthe, Robert Luckner: Applying Eigenstructure Assignment to Inner-Loop Flight Control Laws for a Multibody Aircraft. Proceedings of the 2019 CEAS EuroGNC conference. Milan, Italy. April 2019. CEAS-GNC-2019-027.

BibTeX entry:

@Incollection{CEAS-GNC-2019-027,

    authors = {Köthe, Alexander and Luckner, Robert},

    title = {Applying Eigenstructure Assignment to Inner-Loop Flight Control Laws for a Multibody Aircraft},

    booktitle = {Proceedings of the 2019 {CEAS EuroGNC} conference},

    address = {Milan, Italy},

    month = apr,

    year = {2019},

    note = {CEAS-GNC-2019-027}

}