Fast Online Monitoring and System Identification for the Application in the Field of Aeroelasticity

Abstract

During the development of new aircraft wind tunnel testing of 2D and 3D aerofoils or even complete aircraft is essential. The structural integrity of the wind tunnel model needs to be assured for the test campaign because a failure can cause severe damage on the wind tunnel facility and means the loss of the costly model itself. To enhance the level of safety, a detection of the flutter stability while testing is desirable. This new development utilizes ex-perimental and operational modal analysis methods for fast and reliable online identifcation of a system's eigenvalues and eigenvectors. The developed code presented here uses efficient and novel implementations of signal processing and system identifcation algorithms coupled with new ones for mode selection and tracking, to achieve a computation time in the order of seconds, thus allowing a responsive temporal tracking of varying parameters. The code de-veloped at the Institute of Aeroelasticity at the German Aerospace Centre (DLR) is written in MATLAB, is hardware-agnostic and its performance has been assessed with different models. The main focus of the discussion is the time efficiency of various algorithms which enable the online monitoring of system parameters, with an overlook of the influence on speed of various parameters along with presentation of results of a flutter test conducted in the Transonic Wind tunnel in Göttingen.