A Ship-based Autonomous Helicopter as a Sensor for Atmospheric Turbulence Measurement and Modelling

Tuesday, 06/07/2021 12:30
GWRI Auditorium
Sergey Nazarov

Supervisors: Prof. Yehuda Agnon

Co-supervisor Prof. Em. Per-Olof Gutman

The rapid development of civilian UASs poses the problem of flightsafety. Therefore, there is an essential demand for developing methods for UASsthat would be based on previous aviation experience and will be practical onthe one hand, and on the other hand, meet the full-scale civil aviationstandards. Some such methods have been developed for model identification,flight simulation, and flight control design proposes. However, gaps arerequiring further research. For instance, in-flight encounters with turbulenceare significant obstacles to successful flight. Consequently, the primaryobjective of this research is to develop in-flight algorithms for turbulenceestimation for aircraft not equipped with direct turbulence measurementsensors. Therefore, it is proposed to use standard UAV sensor kit and controlsignals produced by the flight control system as primary data for turbulencecomponents reconstruction. This estimate should be represented in theappropriate aviation turbulence intensity metric and can be online downlinkingto the ground station. It can also be saved on the storage device withcorresponding UAV’s position for further turbulence mapping.  The development of such algorithms should bebased on actual flight data for the selected experimental helicopter, and itshould also be extendable to any small-scale rotary-wing UA. The traditionalfixed-wing approach of turbulence modeling is not always applicable torotary-wing aircraft due to different flight regimes and aerodynamic conditions.Furthermore, the existing turbulence models for full-scale rotorcraft arecomprehensive, computationally expensive, and therefore of no practical use forUAV programs. Therefore, the related objective is to derive from flight testdata turbulence and ship-airwakes models, which can be used for flightsimulation, hardware-in-the-loop tests, and stability and performance analysisof small-scale RUAV control systems. Full-scale rotorcraft disturbancerejection requirements focus solely on steady-state response and not takingtransient behavior into account. However, there are still no quantitativedisturbance rejection requirements for the shipboard environment. Therefore, inthis research, new disturbance rejection specifications could be derived fromcontrol system performance analysis as successful flight control designcriteria under strongly turbulent conditions, such as landing on a ship deck.