Koethe, Alexander (Technische Universitaet Berlin), Luckner, Robert (Berlin Technical University)

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

Scheduled for presentation during the Regular Session "Aircraft flight control analysis and design 2" (ThM1), Thursday, April 4, 2019, 10:30−11:00, Carassa-Dadda

5th CEAS Conference on Guidance, Navigation and Control, April 3-5, 2019, Milano, Italy

This information is tentative and subject to change. Compiled on April 26, 2024

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, a flight control law is 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.