Störresistente Anströmgrößenbestimmung mittels eines Flush Air Data Sensing Systems für unbemannte Kleinflugzeuge

RWTH Publications (RWTH Aachen)

Abstract

Unmanned aerial systems are increasingly being used in the fields of civil security and rescue services. Frequently, the flights to be conducted go beyond direct line-of-sight to a pilot and are intended to be partially automated. When larger distances must be covered, convertible aircraft or fixed-wing systems are most commonly employed due to their efficiency and flight speed. In order to be established as a reliable operational asset within the rescue chain, these unmanned small aircraft must remain operational even under adverse weather conditions, which may be characterized by strong gust loads and rain. To mitigate gust loads, innovative approaches make use of active load alleviation systems. If these systems can detect a gust before it reaches the main wing, they can anticipate its effect and reduce the load factor through targeted control surface deflections. For gust detection, information on the flow conditions ahead of the main wing is required. This information can be derived, for example, from surface pressure measurements using so-called Flush-Air-Data-Sensing systems, or FADS.In this work, methods are developed for transforming pressure measurements into aerodynamic flow parameters of a FADS intended for use in a gust load alleviation system. The starting point is the derivation of application-specific requirements such as measurement range, accuracy, computation time, and memory usage. Based on this, various approaches are designed and calibrated using wind tunnel data. The developed approaches are then comparatively evaluated in order to select the method most suitable for the intended application.To ensure the operational capability of the FADS even under adverse weather conditions, special emphasis is placed on the effects of disturbances. The main focus lies on analyzing the influence of rain on the FADS, which is qualitatively assessed and described using wind tunnel experiments. Measures and adaptations are developed to increase the disturbance resistance of the selected method against such influences. A distinction is made between scenarios in which the presence of a disturbance is either known or unknown.The applicability of the developed method is validated using measurement data obtained from flight tests.

Authors 1

1. Jan Eike Tilmans corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen