An Efficient Algorithm for On-Line Automatic Detection of Flight Control Instabilities

[Abstract] In this paper an algorithm to detect the incipient flight control instabilities is proposed. The algorithm focuses on the detection of oscillations in the aircraft control command signals selected as indicators of flight control instabilities. The algorithm is based on a set of band-pass filters with the advantage of being computationally simple and deterministic so to be suitable for real time applications. Taking also into account that the proposed approach only needs limited knowledge about the system dynamic behaviour, it is suitable for both conventional and non conventional aircraft configurations. In order to verify the robustness to model uncertainties and environment disturbances of the proposed algorithm, a comparative analysis with alternative methods proposed in the literature has been performed by using a Monte Carlo approach. The comparative analysis has been developed considering as benchmark problem the on-line detection of flight control instabilities for the Flying Test Bed 1 (FTB_1) unmanned re-entry vehicle, being developed by the Italian Aerospace Research Centre (CIRA), in the framework of the Unmanned Space Vehicle (USV) project. It is obvious that the proposed method could also be applied in manned aircraft in order to prevent pilot involved oscillation by early detection of command instabilities.