Turbulence Modeling in Urban Air Mobility Applications : Modellering av en avstämbar laser med smal linjebredd

Sammanfattning: A proof-of-concept turbulence modeling approach for rotorcraft in low-altitude, low-speed conditions based on parametric Control Equivalent Turbulence Input (CETI) models was developed. In its original form, CETI-model outputs are disturbance control inputs to replicate the vehicle motion response as if it was operating in turbulent conditions. Consequently, a CETI-model is directly tied to a specific vehicle, and model extraction requires flight data in turbulent conditions. The purpose of the new model was to find Atmospheric Disturbance Equivalent (ADE) inputs that would be applicable to all rotorcraft. The equivalent turbulence components were obtained through linear combinations of the control signals generated through white-noise driven transfer functions that constitute the original CETI-model. \\ A preliminary evaluation of the proposed modeling approach was conducted by simulating turbulence vehicle response in low-altitude, low-speed conditions. The considered vehicle was a NASA reference concept aircraft designed for Urban Air Mobility applications, namely a 1-passenger electric quadrotor using collective controls. The results were compared to those generated through conventional theoretical turbulence models, i.e the Von Karman model. \\ Preliminary results showed promising implications that an empirical atmospheric turbulence model with the proposed approach is feasible. Computed Atmospheric Disturbance Equivalent turbulence components generated vehicle response consistent with the original CETI-model in the vehicle linear axes. Vehicle response in angular rates showed less consistency. The NASA Quadrotor vehicle response showed over-all validating resemblance between the new CETI-ADE model and the existing von Karman model, but with observable differences that legitimated the development of a new model. To meet the final objectives, the new model needs to be refined and validated further by pilot evaluation.